Morv

That's the reason I wouldn't touch this thing in such a way without a detailed super dummie guide Sorry for your loss, though =/

Yes, just clarifying this at this point: I got things messed up. ithildin struggles himself with stability issues and needs help, too. Sorry about this.

Oh yes, I messed that up, I'm really sorry! @ha1o2surfer: Can you provide pictures and/or some details on how to do the cable mod? As you can see in this thread there are people struggling with this stability issue. As you wrote that you could fix it with your mod it may be the general solution. People who don't know for sure what you meant will most probably not try to mod it and harm the board but a guide with pictures should be easy to follow. I really think people would be thankful to finally have a stable setup with their desired graphics card.

This is very interesting information. Optimus can only be enabled with the iGPU present. Your Macbook having the GT 750M but giving the same messages hints that it isn't Optimus or iGPU related. As I previously wrote in the first post, something is going on at boot which leads to those messages. I'm starting my Macbook by pressing Alt until the boot menu appears, then I plug in the already powered eGPU, wait a second or two and then I boot Windows. Same procedure all along but sometimes it loads with the iGPU enabled and I do not know why, it also happens if I don't load OS X in the meantime. I then have the messages like you but I only have the iGPU in my Macbook which is why we thought it's Optimus related. I don't know, maybe this is some weird allocation failure happening at boot? I'd still like to know if this the reason for the crashes or if it's really something electric related to the Akitio board.

Yes, it was you I was referring to but I didn't want to search for your post as I didn't know anymore in which thread I had seen your post and I didn't know your name either :S. Still, thanks for your information. Did you have Optimus enabled with both the cards, e.g. access to the internal display? Like the others stated they only get it when Optimus is enabled and I can agree to this with my new GTX 960. If I boot and it boots with iGPU enabled I get these entries and a load on the System task of about 15-20%. Also, I remember the output on the external display felt somewhat slow or laggy with the GTX 780. Running the system with the GTX 960 feels way smoother(cursor movement, window movements). If you like to, check about this, too. If you want a stable fast card, take a Gigabyte GTX 960 ITX. That's the one I've got and i did not have a crash until now, it's about a week nearly since I've got it. 3DMark11 ranges from ~8700 to ~9400(+200MHz on each core and memory, stable, without increasing voltage). It's really sad that ithildin doesn't answer. There may be a solution to use bigger cards but I don't know that much about electrics, so I still don't know what exactly he meant. @goalque: Are you any smarter about this already? You wrote that you came to the same thought as he did but I guess you don't want to blindly harm your Akitio board just like me

@goalque: Please don't use one example of an AMD card not working as proof for every AMD card being unstable on Windows 8.1. I only had one AMD card and up to now 3 Nvidia cards. 2 Nvidia cards were/are stable(GTX 480, GTX 960) and one wasn't(GTX 780). One simply has to try which cards work and which don't. Do not generalize at this point. I'm still waiting for ithildin's answer regarding the mod he mentioned in my thread. @Sp0t: You simply have to try which work. There is no proof that no AMD cards work.

I did not use the R9 280 any further as I needed to sell it again as soon as possible due to it being useless to me. @ithildin: Will you provide the pictures? You may have found a general solution to the stability problems which is important.

This sounds interesting, yes. Pictures are worth a thousand words

Yes, I have to agree that my theory seems to be not true. I noticed the following things with my new Gigabyte GTX 960 Mini ITX, system is running by powered riser + ATX PSU(didn't want to use the Akitio PSU more than necessary): 1. I power up the ATX PSU before starting the Macbook, booting Windows: I don't have access to min/max settings under processor power options in energy settings. The processor is also stuck at full speed or shows wrong values. 2. I start the Macbook first, hold Alt, wait for the boot menu, then power up the ATX PSU and 2 cases are possible to happen(in both I've got access to said options again): 2.1 I see Windows starting on the Macbook display, it then switches to the external display and I've got both iGPU and eGPU present -> Optimus enabled. I've also got a constant load of ~15% by System. Something is wrong then. I shut Windows down. The "bad" MEIx64 lines are present in the event log then! 2.2 I boot Windows after the previous case, no boot can be watched on the internal display and the first picture I get is the Windows log in screen which is hidden by the set image(the colorful one by default). In this case the iGPU is disabled and the CPU speeds down. Only one MEIx64 line again. 3. I reboot to OS X, then reboot to Windows, both times by shutting down the Macbook first, and I am at 2.1 again. Fastboot in Windows is disabled so that's why I don't understand why booting Windows twice results in different outcomes. I still don't think any of those freezing problems are happening because of power issues. If I could run an hour of Furmark with GTX 780 OC by factory + OC by myself over more than one hour without crashing and short time later it crashes while starting up my browser, then what is wrong with the power? I tried the above starting variations with the GTX 780 too btw but it always crashed at some time. There are definitely things happening at boot that differ(by card?) but I neither know why nor when exactly they do and what they're doing to the system.

@goalque: Please look at this measurement by Dschijn -> http://forum.techinferno.com/implementation-guides/8569-%5Bguide%5D-2011-11-macbook-air-gtx750ti%4010gbps-tb1-akitio-thunder2-osx10-10-a-5.html#post120806 In my eyes the 25W restriction is fictional and most probably only told to please Intel. Other adapters(Sonnet Echo Express SE II, OWC Mercury Helios) write the following "Minimium guaranteed power for PCIe slot: 25W". This implies they simply don't guarantee big cards like graphics cards to work so that Intel is happy. Yesterday I fired a GTX 960 from Akitio's board slot with the Akitio PSU and a 6 pin pcie power plug from a ATX PSU. The system ran without issues which means that with a TDP of 120W and 6 pin pcie plug providing max. 75W the slot provided the remaining needed power of way more than 25W. Your event log showing only one MEIx16 row and the system being stable is a good sign for my "theory". @all: Please provide more information! It doesn't even take 5 minutes to see what the log shows. No matter if you've experienced difficulties or everything went smooth from the beginning.

Yes, powered riser. The card was crashing in Windows though and OS X didn't run long enough to see if it would have been stable there. I've opened a thread regarding the instability here -> http://forum.techinferno.com/diy-e-gpu-projects/8844-targeting-akitio-thunder2-pcie-boxs-stability-issues.html It seems like there's something happening at boot time which causes the instability later on. It doesn't seem to be caused by powered risers or power related stuff at all. Maybe it's not even the Akitio.

Feb 14 2015 Tech Inferno Fan>> Anybody with instability should consider performing mod INFO: passing 75W slot power without a PCIe riser to pass 12V/75W to the slot without using a Gen2 signal-degrading powered PCIe riser. --- Forget about all of the following stuff in the spoiler. It seems to have been a wrong thought by myself and is rather connected to Optimus/iGPU not being disabled than the stability of a GPU itself. Still, if you want to discuss the issue, this may be the right thread now as there other thoughts contained as well. Hello Akitio Thunder2 users and @Tech Inferno Fan, there are users whose setup isn't stable and crashes randomly. I was one of them and had kind of an odyssey until I got a stable system(again). If you want to know about the stuff I experienced, read the background story(a bit longer): I bought a MBPr 15" 2014 Iris Pro only base model in October '14 and received my Akitio Thunder2 PCIe box 2 weeks later. I already owned a GTX 480 and a ATX PSU which were used in my computer. I started using the GTX 480 as eGPU and it worked out of the box really well. Though the performance was still good I already planned on replacing it some time before and finally got a good deal for a used GTX 780 some days before christmas. Happily I replaced the GTX 480 and went on the same as before. Some time onwards I experienced a crash while gaming which showed up by stuttering sound and input being followed by a black screen. The first time it happened I just thought it was bad luck but it showed up again and again. So I thought the card may get too hot in the case I had put it into and placed everything in the open on my desktop. While testing it happened again and again. I got confused. While reading on this board in the Macbook experiences thread I saw someone posting exactly those symptoms I had. He "fixed" it by switching his GTX 770 for a GTX 760. So I thought it may be a power consuming thing although my GTX 480 had 6+8 pin slots as well and is clearly known as a power hungry heater. I had read that AMD cards could be used on external screens in OS X so I bought an Asus R9 280 Strix(6+8 pin too, unfortunately) to test this once, too. I cleaned drivers using DDU and installed Catalyst drivers. I tested and tested and then it happened again, same procedure but a white screen instead of black screen. Now I got tired of this stuff. I still thought of the PSU as a problem(it's more than 5 years old, multi rail) and bought a new single rail one. Of course the same things happened again. I had put the R9 280 away so I could sell it again. If I'd find a solution I'd be using the GTX 780 anyway as it is the more powerful card. In the following time I tried the following: Akitio board - powered riser - 90 degree pcie angle - GTX 780 | ATX PSU only Akitio board - powered riser - GTX 780 | ATX PSU only Akitio board - GTX 780 | Akitio + ATX PSU None of these combinations worked out to be stable. I had replaced the powered riser already some time ago so this wasn't a reason either. So I got: 2 ATX PSU, 2 powerful graphics cards, 2 risers, various combinations. What I didn't replace was the thunderbolt cable and the adapter. Both didn't seem to be responsible for the symptoms in my view and I didn't want to buy another adapter. So the GTX 960 was announced and appeared in stores some times later. It only needs a single 6 pin plug. I still thought it might be a power consumption issue although it did not seem plausible to me because full load was possible even with the GTX 780. The crashes appeared absolutely random and weren't reproducable. Against my own common sense I bought a Gigabyte GTX 960 Mini OC in an online shop. In Germany we're able to send products back to the shop in between 14 days after receiving the good without a reason and we get our money back(if the good isn't obviously used and/or damaged, of course). I'd only need one day anyway because a day without a crash wasn't possible to achieve. I received the card today and plugged it into the Akitio slot directly powering it with the Akitio PSU. The additional 6 pin plug was taken from the ATX PSU of course. Good news: Not a single crash this day. I had previously watching the system tab of the event viewer in Windows, which shows starting components, crasing drivers etc., while trying to find a reason for the crashes. Back then I noticed the "Intel Management Engine Interface driver" being started at one point and then the same was being disabled and enabled again a short moment later. This only occured when the eGPU with the GTX 780 was plugged in and running. It was the same for the R9 280. Now guess what? My new GTX 960 doesn't produce those two entries and I'd say the GTX 480 didn't produce them as well. Unfortunately I had reinstalled Windows some days ago so my event viewer logs of the time when the GTX 480 was in use are gone. I hadn't thought about checking this before even though I noticed the stuff described above. I asked @Dschijn if he had the same single entry only, because he was one of the users with a powerful card, Akitio Thunder2 and reportedly stable connection and he confirmed the single entry for his setup. This would indicate that the issue isn't caused by power consumption but is a software or bios/efi(gpu) issue at boot. Even though the unstable systems crashed they could be put on high load and even overclocking wasn't an issue. Otherwise I've only got a theory and at this point I need your help If this can be confirmed by more users one can at least determine if the card will be either stable or crashing the system. It won't provide a solution to get a stable system with an unstable card for now though. So, for all those of you having an Akitio Thunder2 in use and either have a stable or unstable system, do this: Move to Control Panel - Administrative Tools - Event Viewer - (left panel) Windows Logs - System and watch for the following lines: If you've got a stable system, only expect one line(green): If you've got an unstable system, one line first(green), then two lines right after another(red), one warning, one information: If you've got a stable system but the second set of entries, well then you've either been lucky or my theory is wrong. All of this has been experienced in Windows 8.1 Pro, though Pro or not shouldn't result in a difference. If you use Windows 7, you may provide the screens or informations, too. Thank you very much.

News what for? They already work after modifying the responsible Kext including external screens. See http://forum.techinferno.com/implementation-guides/8585-%5Bguide%5D-2014-15-macbook-pro-2x-r9_280x%4016gbps-tb2-netstor-na211tb-win8-1-osx.html Had a R9 280 running OS X on external screen after following his guide with a Akitio Thunder2.

EVGA cards are able to enable Optimus without any modifications. The guide you've linked is especially for all the other cards which would boot without Iris Pro enabled. By following the guide and applying the stuff described you get Optimus with any Nvidia card.

I used the usual Nvidia desktop drivers.

I was beginning with a GTX 480 and it worked for over a month. In this time the system only crashed 1-2 times which I thought might have been the graphics card running far too hot(it was dirty...). I then upgraded to a GTX 780 and the regular crashes began. I've since then swapped the ATX PSU twice(one used from a friend, one brandnew bought, both more than capable of firing the graphics card), bought another graphics card(Powercolor R9 280 at first, got changed to a Asus R9 280 due to coil whining, both the same symptoms) and used "No riser with Akitio PSU", "Riser and Akitio PSU", "Riser and 90° angle", "Riser and 90° angle and Akitio PSU". The riser is powered of course. I tried different power outlets with different power strips, yet it doesn't change the outcome. Everytime it crashes but the time it takes to happen varies from "at login" over "shortly after boot" to "several hours with gaming, benchmarking and high usage of the graphics card"(previously today...). Nvidia or AMD doesn't seem to matter. The only thing I have not swapped is the Thunderbolt cable and I don't see this being the reason. Is it possible that the cable is defect? Is it possible the Akitio hardware is defect? I also don't see why the Barrel-to-Molex adapter is supposed to help. If the Akitio board only delivers 25W to the pcie socket by design(Akitio PSU is already 60W but they say 25W for pcie slot), how's it changing anything if the barrel plug will deliver more power? I don't see anything I can do anymore and I will give up at this point. I'll sell the Akitio Thunder2 and probably the Macbook as well, turning back to Desktop + Laptop. It's really sad because I really like the whole concept and was happy while it worked but I want a reliable system.

I thought the same and already have purchased the second riser(which didn't change a thing, btw). I'm not using the Boot Camp drivers, I'm using the usual AMD drivers, 14.12 Omega Catalyst. Same for the GTX 780, usual Nvidia drivers. This may be true. Proper powering would probably be done by soldering the molex connector directly on the Akitio's pcie slot, as shown by nando in the Akitio Thunder2 thread(photos in first thread, he shows the area with a red marker). Problem is that I would need a detailed description so I'd know where to solder which cable as I don't have knowledge of the connection. Still, thank you for your effort.

System hangs, audio stutters, FPS decrease. Then black screen on Nvidia, white screen on AMD card. The driver crashes which can be seen in the Event Log of Windows. Sometimes the driver gets restored. It happens randomly even on desktop. Indeed all of my cards, the old GTX 480, the newer GTX 780 and the freshly bought R9 280 Strix are overclocked by the vendor. Though if a card is stable on high load for a time and then crashes sometimes in the same game or even on the desktop, is it really the OC? I don't think so. I was running Furmark for 15 minutes without problems. Can a powered USB hub interfere with the thunderbolt stuff? I have a USB hub attached to my right USB slot of the Macbook so I can attach all the desktop stuff I need. I did not try to remove it and play then or moving it to the leftside USB slot.

So, I turned in my R9 280 with coil whining and got a Asus R9 280 Strix. Nice card, which is quiet overall. I also bought a new PSU(Corsair VS550, did not buy the VS450 in case I'll build a desktop again if I can't solve the issue) Still, and that's the problem, the system crashed again. So I switched everything except the Akitio board and the Thunderbolt cable and the issue is always the same: crashing graphics driver. Any ideas?

I'm not interested in heavy gaming on OS X either. It would have been just nice to not have to replug cables everytime I want to use OS X on my external display. Nvidia cards don't give any output to the external screen in OS X on a MBPr 15" 2014 Iris Pro only, I asked you in another thread where you stated this. Only OpenCL/CUDA calculations could be made with the attached graphics card but neither gaming nor output on the external display. As for now, I'll have to see what exactly my problem is. In my edit I wrote that the AMD card also crashed. I don't know what exactly is wrong but it's starting to annoy me. Especially because those crashes seem to appear totally random and can not be reproduced at will. I really hope it's simply my PSU which is dying of old age because if it isn't I don't have any more ideas... Thank you though.

Ok, got a R9 280(aka HD7950). Works like a charm in OS X after editing some kexts as described by goalque in his R9 280X Crossfire thread. Internal and external display both work parallel. External has got the power of the eGPU, internal does not. Tested Unigine Valley and got 23-35 FPS on Extreme HD setting. Iris Pro gives about 6-13 FPS. Windows works as usual, external display only. Didn't test Evo*'s modification which shall enable internal display on Windows too, as described by goalque in said thread. I'm using an Akitio Thunder2. Unfortunately the card has unacceptable coil whining in Windows so I hope I'll get another one. Thanks to goalque at this point. Edit: Eeehm ok. It just crashed in Windows the way it did before(graphics driver crashed). I guess I'll have to replace my PSU. It's the only part left which I didn't replace yet. Thought it would be ok because it could the most load I could put on it and only crashed now and then and even on Desktop without anything open than a browser. Bought another riser already and the graphics card today. This somewhat sucks =/

I can only say that I did not. Had a GTX 480 and since I swapped it for a GTX 780 I got random driver restores and crashes. I don't know what is wrong with that combination.

As my GTX 780 keeps crashing randomly(driver restored or it's totally gone and I need to reboot) I'm thinking about getting a R9 280 as a replacement. What do you mean with the passage "Internal screen is accelerated on OS X"? Can I use the internal display in OS X together with the external display? Can I play games on it like Optimus in Windows? Using both displays(internal + external) alone without gaming would be nice, too. I don't use internal screen for gaming right now due to performance loss, so I guess I wouldn't mind losing it. All this on MBPr 15" 2014 Iris Pro only. What about Windows? I'm really curious about this. I don't like that I can't use the external display in OS X without plugging cables in and out, so I'm looking forward to this. Thank you.

It is hardcoded in the program. If you change the date of your computer to a date before expiry date it works again. I have no idea why he is limiting it like this though. Betas should be limited somehow so users stop using and complaining about an obsolete version once the release version has been published. This is alright. But the way he does it is just annoying. I for myself just don't want to be dependent on him or his software(although it's good, no question) as long as it is like this.

I have no idea, I don't do that, just tested it. I let it run once it's open but minimize it to tray, mostly because of the temperature history. The beta thing being limited in time was one reason I stopped using ThrottleStop because you simply can't rely on it that way. I had to disable throttling in my 2013 Asus notebook because the cooling system was capable of cooling the CPU but Asus throttled the CPU when the GPU got too "hot"(it was pretty fine...). It was at this moment that the ThrottleStop stopped working because of the time limit and unclewebb, the creator, seemed to be annoyed by the users asking for a new usable version. I then wrote my own program which did only exactly what I needed. It's kind of an arrogant behaviour to me("bow to me, my users, beg for a new version") which is the reason I simply refuse to use his software. Integrate an update routine and it would be fine and no more expiring betas would be needed...