First of all, thanks to those who suggested upgrading to an X58 Xeon. After a bit of faffing with the bios, it looks to be working fine. I plugged in the Oculus on stock settings and still with 6Gb of RAM and I could do a few laps in iRacing, only in Test mode, so no other cars on track. That was enough to convince me that it is worth upgrading the RAM.
So now I've got the X5670 with 12Gb (3x4Gb) of RAM and a GTX 1080. Total cost of upgrade was ~£165 (including the USB 3.0 card and not including the GPU). Probably would have been much cheaper if I bought the RAM used. Still much less than a new CPU, motherboard and RAM that I was considering initially.
Next step is to overclock the CPU. I started last night following this guide http://www.techreaction.net/2010/09/07/3-step-overclocking-guide-bloomfield-and-gulftown/
First up the BCLK gradually from 150 to 200 with a low CPU, memory and UCLK multiplier. Then again with the target RAM frequency multiplier to reach 1600 MHz at 200 BCLK. Then a third time with the CPU multiplier to reach 4.2 GHz at BCLK 200. This went very smoothly and managed to hit 4.2 GHz without increasing any of the voltages I had manually set. Unfortunately I soon realised that I hadn't manually set the CPU vcore or the RAM voltage, so the CPU was running at 1.36v and 80-85 degrees during an IntelBurnTest. I went back to the BIOS, decreased BLCK back to 150, set the CPU and DRAM voltages at 1.2 and 1.65 respectively. To reach 4GHz (190x21) I had to increase the vcore to 1.225 and to 1.275 to reach 4.2GHz. It didn't take long before that crashed though, so I've left a longer run of the IntelBurnTest at 4GHz (200x20) @ 1.275v. Lets see how that goes. CPU temps were hovering just under 80c so there is probably more headroom. This is with HT enabled and all the power saving features enabled.
So now I've got the X5670 with 12Gb (3x4Gb) of RAM and a GTX 1080. Total cost of upgrade was ~£165 (including the USB 3.0 card and not including the GPU). Probably would have been much cheaper if I bought the RAM used. Still much less than a new CPU, motherboard and RAM that I was considering initially.
Next step is to overclock the CPU. I started last night following this guide http://www.techreaction.net/2010/09/07/3-step-overclocking-guide-bloomfield-and-gulftown/
First up the BCLK gradually from 150 to 200 with a low CPU, memory and UCLK multiplier. Then again with the target RAM frequency multiplier to reach 1600 MHz at 200 BCLK. Then a third time with the CPU multiplier to reach 4.2 GHz at BCLK 200. This went very smoothly and managed to hit 4.2 GHz without increasing any of the voltages I had manually set. Unfortunately I soon realised that I hadn't manually set the CPU vcore or the RAM voltage, so the CPU was running at 1.36v and 80-85 degrees during an IntelBurnTest. I went back to the BIOS, decreased BLCK back to 150, set the CPU and DRAM voltages at 1.2 and 1.65 respectively. To reach 4GHz (190x21) I had to increase the vcore to 1.225 and to 1.275 to reach 4.2GHz. It didn't take long before that crashed though, so I've left a longer run of the IntelBurnTest at 4GHz (200x20) @ 1.275v. Lets see how that goes. CPU temps were hovering just under 80c so there is probably more headroom. This is with HT enabled and all the power saving features enabled.