I have been pulling my hair out over my custom built "Super System" I put together a few months ago.
Here is my setup:
Mobo:-----------Asus M2N32-SLI Deluxe
CPU:------------AMD Athlon 64 X2 4600+ 2.40GHz / 1MB Cache (Dual Core)
OS:-------------Windows XP Pro
Power:----------Ultra X2 Connect 550-Watt
Vid Cards:------2 x EVGA GeForce 7950 GX2 Dual GPU PCIe (setup in SLI)
3rd Vid:---------ATI FireMV 2200 (PCI card setup to run 2nd monitor)
RAM:------------2 x 1024 PC4200 533MHz DDR2
HDDs------------2 x Seagate 160gig SATA 7200rpm 8mb (OS drives RAID-0)
------------------1 x Seagate 320gb SATA 7200rpm 16mb (storage)
------------------1 x Seagate 750gb SATA 7200rpm 16mb (work-storage)
DVD/RW:-------Plextor PX-755SA Dual Layer
There are two issues I have been dealing with over the past couple of months:
1. This system on paper should be blazing fast. And for gaming, it's pretty darn quick. But when I am working in Photoshop, multitasking, etc, it seems to hesitate when opening applications, or toggling between them. I figured that with 2 gigs of Ram and the striped system drive that this would not happen (boosting read/write speeds). Could this be an issue with running RAID-0 on two big drives (160gig ea.)? Could this simply be an issue with Windows being a pain? Bad Ram maybe? Any ideas?
2. When I first boot the machine the CPU usage seems normal (on both CPU windows in the Task Manager). However if the machine is on all day (or overnight)... the machine seems to run a little slower and when I open the Task Manager... I notice that while CPU#1 is normal.... CPU#2 is up around 60-80% and when I look to the Processes running it's the System Idle Process that appears to be taxing that CPU Core.
I know my system is clean. I have NOD32 and also run spyware sweeps from time to time. I am pretty boggled as to what could be causing this problem.
Read the power requirements for the drives. I bet no more than 15-20 watts per drive. I had a Intel Prescott 2.6Ghz with 7 hard drives and an nVidia 6600GT running easily with a 450 watt supply. Most people have no clue about how much power they really need.
Yes, your two video cards are probably consuming a lot of power. For that reason 550 is probably sufficient, but could be higher. However, if you run out of power, the system will shut down. I work with the power systems in PC's and everything is rated at about -10% from normal. In other words, 12V in can be as low as 10.8 before anything would start to be a problem. If you have a poor PSU then it could be low to begin with. Either way, things don't slow down, they will just stop working (low voltage is dangerous so systems are intentionally disabled).