ASUS A8N SLI - Premium and 4 DIMMS

[whisky2000]

Hi,

I got snags. With the PC as well.

I have just upgradede to an Asus A8N-SLI Premium, Bought 2 more Corsair CMX512-4400C2.5PT DIMMS (4 in total) and fitted a second 7900GTX card.
My Rig also has 4 x 80Gb Sata 1 drives in a striping array. AMD 64 x 2 4400 (939). I'm using a Hiper R-Type 580Watt PSU. I have a 2nd psu running the WC rig and all fans and lights.

My problem is that I can't get all 4 sticks to run. Either pair will run fine upto 275Mhz as I would expect. Put 4 in and it wont Post. Put 3 in and it runs fine upto 250 Mhz.
Also the NVIDA software reports it is lowering the Clock on the cards due to low power. Finally the USB devices keep switching off randomally and then comming back on.
I use Speedfan to monitor temps and voltages and all voltages are within spec except -12 and -5 which report -2.08 and -8.78 respectively.

I can manually raise the GPU clock using Systool and it dosn't cause any issues.
Dunno where to go except a new, bigger PSU but all the PSU calculators I type my kit into say the 580 should be enough.
I'm thinking of trying one of the Thermaltake 250W SLI PSUs to provide for just the Cards.
Anyone any ideas. Appreciate any advice.

Regards,

Whisky

[Polaris573]

Have you updated the BIOS to the latest version? How much RAM do you have when you have 4 memory modules in? Are you running it at overclocked speeds when you put all four modules in? If you are then you should turn the clocks down a bit because memory doesn't always clock as high when you have four modules in. Do the USB devices always switch on and off or only when you have 4 memory modules in? If you are at standard speeds do the USB devices still switch on and off or is it only when your system is overclocked?

[whisky2000]

Have you updated the BIOS to the latest version?
Yes.

How much RAM do you have when you have 4 memory modules in?
2 Gigs. I can put 3 in and it works fine upto 250 Mhz! But wont post with 4.

Are you running it at overclocked speeds when you put all four modules in?
No. I even tried turning down the memory divider to 333.

Do the USB devices always switch on and off or only when you have 4 memory modules in?
No. All the time.

If you are at standard speeds do the USB devices still switch on and off or is it only when your system is overclocked?
Yes they do OC or no OC.


All the modules are fine. Tested to 275Mhz. I run them in pairs atm @ 250Mhz with the CPU at a Multi of 10. I get rock solid perfomance except for the USB and being told the GPU clocks have been reduced. I turn up the low power setting on the GPUs using Systool and monitor it during games and it is rock solid also. Can even OC the GPU and Video Memory by 12% average with no issues! Dunno where to go next. Possible a duff MoBo?

Thanks for your help,

Whisky

[Polaris573]

Also, when you have all four modules in make sure you set your memory timings to T2 instead of T1. Often you can't run T1 timings with four modules.

It could be the power supply like you mentioned before, but my best guess is that your motherboard is bad, especially with your USB ports failing periodically. Modern motherboards are fairly good about automatically setting an IRQ number for everything, but you might want to double check that there is no IRQ conflict between your USB controller and another device.

[whisky2000]

Also, when you have all four modules in make sure you set your memory timings to T2 instead of T1. Often you can't run T1 timings with four modules.
T2. Wont runn @ 250Mhz at T1.
It could be the power supply like you mentioned before, but my best guess is that your motherboard is bad, especially with your USB ports failing periodically. Modern motherboards are fairly good about automatically setting an IRQ number for everything, but you might want to double check that there is no IRQ conflict between your USB controller and another device.

Now you're out of my league! :) I do hardware.

Here is my screenshot of everything IRQ wise, anything here look odd?

Thanks for your help,

Whisky