2133MHz RAM POST Issue (M17x R4, AMD 7970m GPU)

[AngieAndretti]

Hello. I've been tinkering with this issue for a couple months now, and wondering if anyone can shed some light or help think of something I have not.

Purchased new M17x R4 from Dell, roughly 3 months ago. Unit has i7 3740 CPU and AMD 7970m GPU. I Added 240GB Mushkin SSD for boot and slaved the original 750GB drive into the secondary bay for data. Upgraded original 1600MHz RAM to 16GB (4x4GB) of Kingston's HyperX 2133MHz DDR3. The 2133MHz RAM does run - and passes all stress/performance tests with flying colors but is generally "finicky" at POST. Laptop likes to come on for a few seconds and then shut back off until a successful POST happens after a few tires. Once it's worked once, it works fine from then on - until you change something related to hardware configuration/settings. I read the wiki page for modern BIOS POST process and I'm thinking this "working fine once it's worked" behavior could be due to BIOS building a "hardware table" that it can then just read from instead of enumerating and detecting everything from scratch - until something changes.

I have verified to my own satisfaction that it's not defective RAM. I purchased some extra sticks and observed same behavior with only new sticks installed.

Another note - the 2133MHz RAM will function without this issue if forced into 1866MHz mode in BIOS (but I don't want to do that unless I absolutely have to.)

Now, for most purposes, it's fine to just leave everything as-is and once I've tried a few power-ups and gotten a successful POST (sometimes it even works the first time after tinkering) all is well. The one place it's an issue is with manual graphics switching. I have the AMD 7970m card with Enduro (which sucks for certain games unless Enduro is disabled.) I don't want to leave the laptop in exclusive dGPU mode all the time because I do use it on battery at times and the discrete mode cuts battery life nearly 50%... so I switch modes with the Fn+F7 and reboot method when I want to play certain games. This causes a full reset and the failing at POST behavior is observed when the unit tries to power back on (in discrete or switchable mode - it's the ACT of switching that's the issue.)

Final note - I use svl7's modified A10 BIOS (have verified same behavior with stock BIOS versions A05 and A10) so I have a lot of available options I can tinker with. Here are the things I've found that INCREASE stability (lessen the chances of the failure at POST, or the number of times it will repeat:)

• Reduce power limits on the CPU in the Performance menu (this helps but even at lowest stock settings, does not quite alleviate 100%)
  
• In advanced CPU power options menu, change boot performance mode from "Max Performance" to "Max Battery."
  
• In advanced CPU power options menu, apply a current limit setting of 160 (20 amps) to 2nd plane current limit (integrated GPU.)
  

The fact that these things make an impact suggests that available power at time of POST may be a component of the problem. I do own 2x 240w PSU's and same behavior is observed with both, as is on battery. I wonder if the issue could have to do with the 7970m card not supporting power gating? I have observed that if I hang out in BIOS for a while, the 7970 card gets extremely hot - so it's definitely sucking back the juice at boot time! Once I exit and Windows begins to load, the GPU fan will then spin up fast for a few seconds to cool the chip. It runs cool then-on unless under stress.

Adding voltage to the RAM (1.55v vs. the standard 1.5v) DOES NOT help, and in fact decreases stability.

If anyone has any thoughts or suggestions, I'd much appreciate!

-Adieu,

Angie.

[StamatisX]

I remember that had the same issue with mine (M17x R2) that has the stock Dell BIOS. That kind of behavior occured when I was changing the default BIOS settings and it only worked without issues after resetting to defaults. It was not a specific setting but rather a combination of them. I found those that didn't affect POST and I left it like that since then.

I suspect though that resetting to defaults won't help in your case....

[AngieAndretti]

Thanks for the reply! I have tried reloading the defaults within BIOS but it does not solve the problem. Also I've verified that the behavior is present in stock BIOS A05, A10, and svl7's modified A10. Good news is that so far (probably jinxing myself as we speak) it's been more stable with two of the four installed ram sticks being the two new ones I recently purchased. The odd thing is that the arrangement of the sticks has made a difference from day one - and is still the case! All configurations do work once it's POSTed successfully that first time and all sticks test out as defect-free but it still makes a difference WHERE (in which slots) I place the individual sticks. Also oddly enough the pairs that were purchased together as kits do not like to be installed together. I have the new ones in slots 1 and 3 and two old ones in 2 and 4 - and that's how it wants to work! Placing the two new ones together in 1 and 2 I was unable to get a successful POST, even without any other sticks installed in 3 and 4. There was one stick in particular (one of the two I swapped out) that seemed to be decreasing POST stability so I'm going to cross my fingers and hope this configuration holds up as-is.

I did experiment with a method for implementing manual on-the-fly graphics switching (similar to the behavior of the R3 units) which never needed a reboot to switch modes. This method increased battery life some while using the iGPU and I got full performance from my dGPU (taking Enduro out of the equation) but I found it confused some applications. Windows Magnifier and Flash-based content in particular crashed sometimes while in this mode. Also the Alienware OSD was unable to properly determine the center coordinates of the LCD screen - so it was not flawless but is likely deserving of further experimentation since Enduro just sucks in some games and this would be a nice workaround (for both my RAM issue AND Enduro.)

Any other thoughts about the RAM and POST behavior are still welcome! Thank you.

[AngieAndretti]

Since this thread was never properly concluded, I would like to mention that I ultimately resolved the issue (after much tinkering) by purchasing two replacement 2133MHz RAM chips from Kingston, and then experimenting to find the two existing chips that were "weakest" (although they all passed BurnInTest from the start) and I replaced these two existing chips with the ones I purchased later. Since then I've had no issues with POST after changing graphics modes!