Q6600: RAM question

[phototext]

Hi folks,

After doing some reading here and elsewhere I dived in and tried some overclocking of a Q6600.

I have an Acer Veriton T661. Not the best machine for such stuff, the BIOS is pretty basic and not much good for overclocking.

I used SetFSB and kept an eye on temperatures with speedfan and coretemp.

All went well and I had a stable system with these figures in SetFSB

330.7/661.3/100.0/33.3MHz

2968.7MHz

Pre overclocking figures in SetFSB

266.7/533.3/100/33.3MHz

2394.0MHz



Did some tests and benchmarks and was very happy with the increased processing speed in my main program, Photoshop CS4.


I was using the RAM that came with the machine, 2gb of DDR2-667 Apacer UNB PC2-5300 CL5.

On Friday I installed four new 2gb sticks of RAM (and installed Vista SP1 64bit).

Corsair TWIN2X4096-6400C5 4GB (2x XMS2 2GB) Twin2X PC-6400 (800MHz) DDR2 RAM, 2x240-pin DIMMs, Non ECC, Unbuffered, 5-5-5-18, 128Mx8 DRAMs.

http://www.corsair.com/configurator/system_results.aspx?id=631953


The system works well, Photoshop now can access a good chunk of memory, excellent.


But, trying an overclock the same as before and the system fell over. I couldn't even get into the the OS (both XP and Vista) again and trying a new install couldn't even do that.

Figures in SetFSB (before it fell over on the next bump up, although was a bit unstable)

312.0/624.0/100.0/33.3MHz

2801.2MHz

Panicked, went out side and thought it through and pulled out a couple sticks of RAM and tried a restart and system booted up and into Windows. Put the two sticks back in and system booted and into Windows.

All is fine.


But I would still like to try an overclock again.

My question (finally) is about the RAM.

Did the new RAM fall over because it was overclocked ? (I suppose it must have as it runs fine now).

If I set the new RAM of 800MHz to 667MHz in the BIOS (which looks possible) any overclocking through SetFSB would not be pushing the RAM above 800MHz but above 667MHz, so any overclocking of the RAM through SetFSB would then be less likely to make the RAM fall over ?

Put another way, does underclocking RAM make for more stable RAM when overclocking the CPU ?


Cheers.

Jeremy





http://1x.com/member/1148/jeremy-russell/

 

[irkjab]

Can you set the frequencies in the bios?
If so, that is usually preferrable to doing it through windows. If you can do the overclock in the bios, there should also be a way to set the ratio of the cpu fsb to the ram speed.

For example running the fsb at 333mhz (333*9 = 3ghz), a ratio of 5:6 or 1:1.2 would run the ram at 800mhz.

I have the same ram and processor, and it overclocks just fine

edit: Also, does setfsb let you change the processor and the ram frequencies separately? or are they linked?

 

[phototext]

irkjab,

SetFSB has two sliders.

Top slider adjusts the first two numbers in the sequence. ???.?/???.?/100.033.3MHz

Bottom slider changes last two numbers in the sequence. 266.7/533.3/???.?/??.?MHz

The arrows next to - Current CPU Frequency: Internal - change from MMT to QPC and SLP.


Info from CPU-Z

I'll have another dive into the BIOS and see if there is anything that can be changed. But, it is an Acer and from what I have read Acer, Dell etc make their boards locked down for such stuff.

For example running the fsb at 333mhz (333*9 = 3ghz), a ratio of 5:6 or 1:1.2 would run the ram at 800mhz.

I think I'm starting to understand some of this stuff. Cheers. Will get back about BIOS.

Cheers.

 

[irkjab]

Looks like setfsb forces you to overclock the ram and cpu together. I don't know what to do in this case, as my bios lets me adjust the two separately, so i can leave the ram at close to stock frequency.

If you can't overclock from the bios, there is probably someone here who has more experience with setfsb.
I have no experience with it so can't be much help there myself.

 

[phototext]

Looked at the BIOS again.

American Megatrends.

Frequency/ Voltage Control

Ratio Actual Value: 9
CPU Frequency: 266MHz

Greyed out, no way to change it it seems.


Advanced Chipset Setup

Dram Frequency = Auto (Options Auto, 667 or 800)
Configure DRAM Timing by SPD = Enabled (Options Enabled or Disabled).

 

[phototext]

irkjab,

Thanks for taking the time, you have been a help as you helped a couple pieces of the puzzle click into place from other readings.

Cheers.

 

[phototext]

An update for anyone who may be interested.

I set the RAM to 667 in the BIOS.

In SetFSB I set it to 320.0/640.0/100.0/33.3MHz which gave me a DRAM Frequency of 399.8MHz and 5/5/5/15 clocks in MemSet 4.0 and CPU-Z.

The Q6600 is now running at 2873.0MHz.

No stability problems, runs great. Tests and benchmarks good.

I made a punt that if the DRAM frequency didn't exceed the figures in the SPD section in CPU-Z (400MHz), which I guess I was before, things should be fine. That may not be the case at all as I know very little about this whole shebang, but whatever the reason, it has now been working great for a week.

irkjab, again, thanks for taking the time to help me out.