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Asus P5W DH & Core 2 X6800 limited to 3.3Ghz :(

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September 6, 2006 8:03:00 AM

I was able to run my system upto 3.74 Ghz (vCore 1.42) without any problems in all benchmark programs (3DMark05) and Sandra 2007 memory tests ran fine. But when I run Prime95, I would get errors in Test 2 or Test 3.

So I try various BIOS changes and still fails Prime95 until I drop back down to 3.3 Ghz -- this is basically the settings suggested in Wuzy guide.

CPU temps during Prime95 are consistantly pretty low 95 f.

I've tried to keep the memory timing around DDR2-1000Mhz (Patriot RAM is rated to that at 2.2v PC2-8000).

Any attempts to go beyond vCore of 1.42 results in NO POST (have to power off and hit Insert during power up to reset BIOS). I monitored the vCore while running Prime and I don't think it fluctuated much 1.39-1.41 is what it reported.

The PSU is a Silverstone 650 Watt, watercooling is Swiftech 1/2" tube dedicate CPU loop.

Seeing as the RAM speed is very close to the same setting between the 3.3Ghz and 3.7Ghz (also tried 3.6Ghz CPU with RAM at 4X249Mhz = 996Mhz) I'm not sure if this is a RAM problem, CPU problem, or motherboard problem -- like I said nothing is being reported as hot and nothing is hot to the touch so I don't know where to check next.

Any suggestions (followed the Core 2 overclocking guide very closely). Only question I had was on memory adjustments -- since I have the P5W DH the guide suggests leaving DRAM timing to SPD? Is this correct?

Rob.
September 6, 2006 3:41:07 PM

Yes 300Mhz is FSB. I'll try DDR2-667, but I guess I must be confused because any changes to the FSB affects the available RAM speed options so as I increase 300Mhz FSB upwards my RAM options change accordingly -- there is no way to retain exactly DDR2-667 if I go up in FSB -- or is there?

Yes, I can change the multiplier on the P5W DH.

Great suggestions, I'll give this a try tonight and see where it takes me. I know this is not a heat issues as there really is nothing that feels hot or even radiates much heat and the temp probes would see to suggest the same also.

BTW, the Swiftech pump and water blocks are very nice units -- easy to install and appear to be very well designed. The only issues I had were with the Swiftech resevoirs -- both leaked at the threaded 1/2 connectors (might be my fault as I just used teflon tape 1st time) I ended up using silicon II and then a glue gun to lock the connectors in position. It was a little tricky priming the Swiftech pumps and the GPU loop still has a little air in the system but that seems to be slowly clearing up.

Rob
September 6, 2006 4:11:59 PM

Try FSB 333 multiplier 11x, should be DDR2-667 - pretty sure this should be P95 stable
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September 6, 2006 10:06:15 PM

Hmmm...chilled water resevior...there is an idea. Yeah, pump (MCP655) and resevoir are both Swiftech (and Swiftech Storm waterblock). Fluid is 1 once Redline water wetter per 16 onces distilled water. Each loop holds 48 onces mixed (about 15 feet of 1/2" tubing per loop) and runs into a dual 120mm Swiftech Radiators (one radiator per loop) that are mounted externally on the case.

DRAM is set to SPD and according to Sandra 2007 the delays are being set to 5-6-6-21 when running at DDR2-1000 (CPU 3.74 Ghz). Memory bandwidth tests are 7229MB/sec, Latency is measured at 64ns, Cache to memory tests are around 32300.
September 6, 2006 10:56:25 PM

All sounds good, I will try another overclocking round tonight.

BTW, your article says increase vCore by +0.025 -- I think you mean by + 0.125v -- unless my motherboard just doesn't support such small vCore increments?

I opt'd for dual loop because I wanted to maximize my cooling potential while still keeping fan noise to a minimum. I don't know what the tubing distance limit is on the Swiftech MCP655, but 15ft of 1/2" tubing per loop doesn't seem to hurt flow -- but I haven't really measured the flow rate so I'm kinda guessing in the dark. I tried to minimize the tubing length, but with external mounted radiators and no sharp bends required 15 feet per loop.
September 7, 2006 11:52:06 AM

Quote:
Yep, at 300Mhz FSB while setting RAM to DDR20667 in BIOS your RAM will actually be running 300Mhz(600Mhz DDR) in accordance to 1:1.
Make sure you set timing to SPD for now.


in the P5W if you set FSB at 300, you will need to manually set RAM to DDR2-600 in BIOS for 1:1- it does not automatically adjust itself...if you set RAM to DDR2-667 in BIOS and FSB to 300 then it will not be 1:1
September 7, 2006 12:57:54 PM

That's right, if you you set FSB to 366, you get options to set RAM at DDR2-549, 732, 915, 976, 1098 etc
September 7, 2006 4:16:11 PM

I think there is some confusion going on... if I set the Multiplier to 10 and CPU to 375 the DDR2 with be automatically set to 750. I have the option to select various DDR2 settings: 563, 750, 938, 1000, 1125, 1250. If I change the multiplier or the CPU, the DDR2 value will change along with the selection of DDR2 values.

I've got my system stable at 3.75Ghz using the following
BIOS Rev 1305

ADVANCED | CPU Configuration
-------------------------------------
Ratio CMOS Setting: 10
Microcode Updation: Enabled (updation, too funny)
Max CPUID Value Limit: Disabled
Execute Disable Function: Disabled (say what?)
Enhanced C1 Control: Disabled
CPU Internal Thermal Control: Disabled
Virtualization Technology: Disabled
Intel SpeedStep Tech: Disabled

ADVANCED | JumperFree Configuration
---------------------------------------------
AI Overclocking: Manual
CPU Frequency: 375
DRAM Frequency: DDR2-750MHz
Performance Mode: Standard
PCI Express Frequency: 100
PCI Clock Synchronization Mode: Auto
Memory Voltage: 2.2v
CPU VCore Voltage: 1.4875v
FSB Termination Voltage: 1.40v
MCH Chipset Voltage: 1.60v
ICH Chipset Voltage: 1.20v

I've tried to run at 3.8 @ 1.5v but that caused problems in Prime95. While Prime95 is running the vCore will drop from 1.48 to 1.45-1.46.

I also tried Multi 12 X 333 - DDR@ 666 @ 1.5v (4Ghz) and system would crash almost immediately at the desktop.

Currently 3.75 Ghz (10 x 375) requires vCore at 1.4875v - anything lower will cause problems with Prime95.

I think I've squeezed as much as I can (and staying reliable) unless you folks have more suggestions, I'm all ears.

Thanks, Rob.
September 7, 2006 4:55:49 PM

Quote:
I think there is some confusion going on... if I set the Multiplier to 10 and CPU to 375 the DDR2 with be automatically set to 750. I have the option to select various DDR2 settings: 563, 750, 938, 1000, 1125, 1250. If I change the multiplier or the CPU, the DDR2 value will change along with the selection of DDR2 values.


that's right, if it's already been set at 1:1, it should change with it, but you must set it to 1:1 first, at least that's how my BIOs (1101) works, if it's 2:3 or 4:5 to start with, then it maintains that ratio when you change the FSB but still gives you the options to select other settings
September 7, 2006 5:14:30 PM

Interesting, no such option to change the ratio in my BIOS (1305) -- unless I'm missing something? All grayed out -- shows me the ratio, just doesn't permit changes to it.
September 7, 2006 10:40:42 PM

Ok, will try PCI clock to 33Mhz and go with 422 X 9 and see what happens. Asus do provide a cooling fan for the MOFSET closests to the rear, but I have a large 120mm fan mounted on the case that is about 1/2" away at 90 degrees to MOFSET so I thought this would actually be more efficient than using ASUS MOFSET fan -- but I'll try the fan as it is simple enough to clip on.

Did I read that someone makes a MOFSET water cooling block?? Or was that considered a waste ?

I need to review a RAM guide -- my RAM is rated at DDR2-1000 PC2-8000, but if I try to select any DRAM frequency that is even close to DDR2-1000 in the BIOS it will not work unless the CPU frequency is 300 or less (multi = 11). As it stands now, when the system posts the post screen shows PC2-5700 (thru my experiments it has shown 5300, 5700, 7100, 8500) -- I have yet been able to get 8000??

Rob.
a b à CPUs
September 8, 2006 2:48:50 PM

The main setting that needs to be disabled is the Hyperpath. I'm unsure of what performance benefit it gives but all I know is that when enabled my system will not post at anything above 3.4GHz.

If you've gone Swiftech there's a block you can buy which can help you achieve over 4GHz as I have. It'sthe MCW5002-775T. You'll need a Meanwell 320W Dedicated 12V Power supply and some Dielectric grease but it did make a remarkable difference.

Core 2 puts out soo little heat (compared to my A64 X2 system) that I Idle at -25C and load around -10C (always changing varying on the room temperature at the time but those were my temps last night).

Pretty good investment for an overclocker. Especially if you've gone all out and gotten the X6800.

I run at 405x11 just in case you were wondering. My VCore is only 1.4375v I believe. Mem is 1:1.
September 8, 2006 3:23:11 PM

Ok, ordered and the PowerSupply - hope it works.

I think what I find most attractive about your statement is that the unit only requires the CPU to run at 1.4375v -- I'm hoping this should keep the MOFSETs happier too.

Now if I could only get my X1900XTX to work as well... thought I had it stable at a miserable 695 core and 880 mem, but AOEIII crashed it. Went back to ATI's Overdrive settings 689/775 and AOEIII ran fine. Gonna try the new ATI tool beta I got and see.

Just finished loading FS9 so will start to use that for stress testing.

Off to LA today, so it'll have to wait til next week.
September 15, 2006 8:27:06 PM

Ok, stuff has shipped and schedule to arrive on Monday. Just want to make a shout out to Gary at Sidewinder Computers he was very helpful in getting the parts to me even during the arrival of his 2nd kid.

I've got my web site started and will update when I have time (tis a place holder page right now) www.nocomsleft.com.

Rob.
September 15, 2006 11:13:31 PM

I got:

Swiftech MC14 BGA Memory Ramsinks http://www.sidewindercomputers.com/swmcbgamera.html
Swiftech MCW5002-775T http://www.sidewindercomputers.com/swmc7.html
Swiftech MCX159-CU http://www.sidewindercomputers.com/swmcchco.html
Meanwell 320W PSU http://www.sidewindercomputers.com/samam32inpsu.html

Also go a PC Power and Cooling 1000Watt PSU (figure I might need this for those 300Watt GPUs coming out), and will be swapping the X1900XTX out for a X1950XTX which I've read seems to be more overclocking friendly. Fortunately selling my "old" components is pretty easy so the experiment isn't too costly.

No melt downs yet, but I'm getting some pretty wild fps numbers in FS 2004 30fps - 75 fps -- think I need to lock it to 30 fps.

Oh, the MOFSET fan that the Asus provide didn't help out my vCore fluctuation during Prime95 -- still goes from 1.43-1.46, maybe my new PSU will help this out??
September 18, 2006 8:28:41 PM

For reference (as some people seem confused) the P5W DH bios (at least the 1305 one) shows the actual memory clock you are setting.

For example, with a 133MHz FSB (D805 stock) one of the options is DDR2-533 (266*2, 1:2 FSB:D RAM). If I overclock the FSB to 150MHz, that same option shows in the BIOS as DDR2-600 (300*2, 1:2 FSB:D RAM)

This means the speed displayed in the BIOS is the speed you get, a pretty simple system imho.
September 19, 2006 1:04:31 AM

Gave me an idea for my web site, CPU ratio, FSB, Memory speed calculator. I'll get that up ASAP.

I agree, the more simple it is made the better.
a b à CPUs
September 19, 2006 1:26:11 AM

Quote:
I got:

Swiftech MC14 BGA Memory Ramsinks http://www.sidewindercomputers.com/swmcbgamera.html
Swiftech MCW5002-775T http://www.sidewindercomputers.com/swmc7.html
Swiftech MCX159-CU http://www.sidewindercomputers.com/swmcchco.html
Meanwell 320W PSU http://www.sidewindercomputers.com/samam32inpsu.html

Also go a PC Power and Cooling 1000Watt PSU (figure I might need this for those 300Watt GPUs coming out), and will be swapping the X1900XTX out for a X1950XTX which I've read seems to be more overclocking friendly. Fortunately selling my "old" components is pretty easy so the experiment isn't too costly.

No melt downs yet, but I'm getting some pretty wild fps numbers in FS 2004 30fps - 75 fps -- think I need to lock it to 30 fps.

Oh, the MOFSET fan that the Asus provide didn't help out my vCore fluctuation during Prime95 -- still goes from 1.43-1.46, maybe my new PSU will help this out??


Looks familiar..:p 

You pretty much have my setup...lol Cept I have Crossfire Up and running.. but your cooling setup has many of the same parts I'm running.
!