toscrawford

Too cool. Pity I didn't find this some time ago as I'm doing the same. I managed to get my PE 6850 to install Windows 8.1. This was inspired by the inability of my PE 2850 to install 8.1. The PE 2850 can install Windows 7 and 8, but the CPU spec changed for 8.1 and 10. That's for another day. The important take away is the dual core CPUs I have (3.4ghz?) do have the necessary microcode and can run Windows 10 (I've managed 8.1 before I mothballed the unit). I accept that I can only run 2xCPU, but I'm not happy about it. Unfortunately I have 3 working CPUs and would have to buy a fourth to test the suggested registry change. The other significant problem was finding SCSI drivers. I managed that through research and trial-and-error, but don't have any links handy. Have I said what a great job angerthosenear did with his documentation and links? On my PE 2850 I removed the back of the PCIe x8 slot with a red hot screwdriver. Simple process really. Don't be afraid. With that gone I was able to manage an AMD HD5670, which required less than 75w. Through some soldering to the power supply I was able to upgrade to an HD7950. As noted the PE6850 only bothers to pump 25w through the PCIe, which got me stuck. Not wanting to run a large enough 110v-220v inverter, I ran a 220v outlet from the circuit breaker box. At some point along the way I had to upgrade the PE6850 motherboard to a newer version, probably to support dual-core. I also had to solve the double-wide card spacing problem, but I think that was done by bending something on the motherboard. Can't think of what it might have been. Next step was to run +12vdc and ground wires through the chassis to the power supply. On the PE6850 this is not nearly as easy as it sounds. That's where I got stuck and mothballed the project. This article might inspire me to get it moving again as I'd really like to get this off my work desk. Let's say I do. Do I spring for a second (third?) HD 7950 and attempt Cross-Fire? I've got oodles of watts and cooling to play with, it would be super cool to do it. The problem is I can't conceive of Dell supporting Cross-Fire unless they did so by accident. Who thinks it's possible?