Jake-O-Matic

Hello,

I'm pretty new to overclocking. Though I have been doing a lot of reading, I still need some help.

My setup:

CPU: E8500 (C0)
Mobo: DFI LanParty DK P45 T2RS
Mem: OCZ Reaper 1066 2x2Gb
PSU: Thermaltake ThoughPower 600W
CPU Cooler: Thermalright Ultra-120 Extreme + Scyth S-Flex 120mm 1200RPM fan
Graphics: Gigabyte HD 4870
Case: Thermaltake m5 with 2 120mm fans (currently open)

Goal:

Reaching the best stable 24/7 OC possible.

Currently, I've been able to get the CPU to 4Ghz (9.5x425) with vcore of 1.34V (sometimes dropping to 1.344 under load). The RAM is running at an FSB of 510Mhz (5-5-5-15) at 2.19v (haven't touched any other memory settings yet). The FSB VTT is 1.2V and the NB voltage is 1.18V. These settings are Prime95 stable for 17 hours. The full load temp of the cores is around 54-61 (with about 5 degrees difference between the cores) according to real temp. Speedfan's readings are usually about 10 degrees higher.

Whenever I up the FSB even to 433, the machine won't POST (usually giving me POST code 26 and and keeping restarting only to fail the POST again). Raising the voltages doesn't seem to help.

I tried to lower the multiplier and increase the FSB (so that I still reach the 4Ghz) and the voltages and nothing good came out of it. The computer is trying to boot and then it fails and then it opens up the booting diagnostics (where it shows what memory/cpu/HDDs it has found) and there's a message saying that the overclocking has failed and the FSB automatically drops to 333. When I crank the voltages even higher, half of the time, I failed the POST.

My question is, how do I proceed from here? I know I can get more out of this gear, but I just don't seem to be able to go over 425 FSB (on a 9.5 multiplier).

Any ideas to what settings I should try? What are the max safe voltages? Which voltages/options should I tweak in order to get a higher FSB?

astraelraen

My E8500 & T2RS has the exact same problem. I can do 425x9.5 but anything over has the same result as yours

I've tried fiddling with voltages, etc for a few hours and doing anything higher than that at 9.5x just doesn't seem to work. I tried dropping to 9x and trying for 450-475x9 and it didn't work so well either. I'm sure the board is capable of higher FSB, just requires more tweaking.

I don't know if I have any hints/tips, just letting you know you aren't alone

fade2green514

add VID voltage to the cpu, it's likely the cpu thats making it unstable if you can lower the multiplier and increase the fsb and get it to boot stable that way. what temperature is it running at?

as far as the fsb goes, you don't really NEED the extra front side bus speed until you get into quad cores. the front side bus can really bottleneck them depending on the operation being performed. i'd really like to get my hands on a 45nm processor, but seeing how my cash flow has been going lately that's not going to happen. i'll probably just leave this rig the way it is until i get my hands on a nehalem.

also try disable eist and cpu thermal throttling. those can hinder an overclock. ppm function should be disabled too as this will switch it between its multipliers on and off when your cpu needs the extra speed.

the e8x00 series can handle high clocks, but every cpu is different. i've seen them at 4.5ghz without an overvolt, and i've seen them at 4ghz requiring an overvolt. it just depends on the stepping and the exact batch that intel manufactured it from.

good luck!

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gandalf615

Sound like FSB wall to me. I can't go above ~424 on my DFI without a huge overvolt to the NB. I would change nothing except upping NB to like 1.3, if still no go try 1.4, if still nothing 1.4v NB with 1.3v VTT? If you get stable then you can try higher FSB, because I'm pretty sure you're at the max multi? When you hit another wall with the board volts go back to the e8500, can push a bit closer to 1.4GHz but don't go past that.

fade2green514

1.4v for the northbridge is too much. don't burn your computer up bro. 1.35 is the most i would go with, especially with passive cooling. a water cooler might change my opinion though.

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Jake-O-Matic

I tried that and haven't been able to boot with 8x475.

The max I've seen (on successful stable boots) was 66-68 (RealTemp).

I'd really like to have a higher FSB for the memory. The ideal would be to run the CPU at 7.5x533 (=4Ghz) and the RAM on 1066 (1:1 ratio). But I'm not even close to that...

I do that. Doesn't help.

I already tried passing the 1.3V on the NB many times. I will try to get to 1.4 and also get the VID to 1.38V-1.39V later today, but I'm guessing it won't help (I fail POST on FSB=450Mhz, Vcore=1.37V, NB = 1.3825V and VTT=1.36V).

Also, I checked a POST errors list on this DFI BIOS Guide and it seems that PST stucking at 26 might have something to go with the graphics card. I always leave the PCIe speed at 100 (which I was told is the right thing to do). Maybe there's some other PCI setting I'm missing here?