The problem is more of a micro stutter but I'm only using one GPU and it happens in many games and benchmarks. Online players skip around, animations are choppy and it looks like frames are being skipped. 120fps looks like 40 fps. This can be felt with mouse movement as well. The system is in my sig and is running at 3.5GHz.
i7 920 @ 3507MHz (stutter happens with optimized defaults as well)
3x2GB ddr3 @ 1336 MHz
Stock GTX 460
Creative x-fi xtremegamer
Windows 8 pro 64 bit
Western Digital WD6401AALS 640GB mechanical hard drive
Seasonic Platinum 660XP 660w power supply
Example with the vantage CPU test showing the planes skip around and even rewind for a split second: I used afterburner to record this and it only lowered the score, it didn't add any extra stutter.
Another video example here: http://www.youtube.com/watch?v=s8R_EsJg3bE
Before and during recording this it looks like many very short microstutters but in the recorded video they showed up as large spikes or skips.
A second but probably related problem is short pauses in the game when playing online. The net graph in games shows what looks like a network problem but my ISP has come out to my house many times to test the lines. I have bypassed the router and tried a new modem and these pauses do not change. Valve had me change all of the network settings and then install a program called Vtrace to see if any programs or drivers could be causing this but they couldn't find anything. Valve's conclusion was that something was wrong with my network and not with my PC. Both of these problems happen in windows 8 and vista.
Example of the pauses and gaps in the network graph:
To troubleshoot my GPU
I RMA'd it through MSI and the replacement changed nothing. I got a third GTX 460, this time from ASUS, again nothing changed. All three of these GTX 460s passed all benchmarks, EVGA oc scanner and OCCT artifact scanner. I tried using the second PCIE slot but again nothing changed. I also went out and purchased a Gigabyte 7850 but it still showed this weird stutter. Both problems exist with my older 60Hz monitor with a replacement dual DVI cable.
To troubleshoot my processor, ram and motherboard
I ran prime95 blend for almost 19 hours, long enough to pass all of the tests with 90% memory usage and no errors were found. I passed 10 runs of IBT at max without an error. It passed OCCT's 1 hour test. I also left the PC to fold overnight but it was still happily folding on a second work unit when I got up. Overnight memtest86+ AND memtest86 came back with no errors. I ran HCI memtest to 1000% without errors. I also made sure to test the stutter problem with everything running stock by loading optimized defaults but that didn't help. I also tried a second memory kit from OCZ that also passes these tests but the stutter was still there. The highest temperature was 61c and that was during IBT.
I flashed to different bios versions including the latest beta bios for my motherboard. I tried disabling all power saving features in the bios.
To troubleshoot my hard drive
The hard drive is currently running in AHCI mode but I have also tried IDE mode. I have also tried using the Microsoft AHCI drivers and the Intel drivers but there isn't a difference between them. Iran the Western Digital advanced diagnostics twice and neither showed any errors. The smart data is also all OK without any warnings. I also replaced sata cables and swapped to alternative sata ports.
To troubleshoot my power supply
I replaced my XFX 650w XXX power supply with the Seasonic platinum 660XP but nothing changed.
To troubleshoot my network
I mentioned this above but ill add it here too. I had my ISP come out and test my lines and they said everything was fine. I bypassed all cable splitters. I bypassed my router and tried a new modem with replacement ethernet cords but the problem remained. I installed an Intel PCI network card in case my motherboards port was failing but yet again, nothing was changed. I even tried using a wireless USB adapter.
To troubleshoot the OS and drivers
I tried the default windows update drivers for my network adapter as well as the newest available from Realtek. I tried clean installing many whql Nvidia drivers in vista and windows 8. I tried reformatting and installing chipset drivers as well as reformatting again without installing chipset drivers. I have tried enabling and disabling HPET in both the bios and windows. With windows using HPET 64 bit the DPC latency is very low. I have 8 tabs open in Firefox, one of them is a 1080p youtube video playing and another one is pandora playing music and the DPC latency is 5-15 in LatencyMon.
To troubleshoot audio
I pulled my sound card out and removed the drivers. I made sure the integrated sound card was disabled in the bios and drivers for it were never installed. Both problems remained without sound.
What's left to troubleshoot? Did I overlook something?
The only hardware that hasn't been swapped out is the CPU, motherboard and the hard drive. Maybe my ISP is lying about my lines being problem free?
I have a 120GB Samsung 840 SSD coming next week but since no errors were found with my current drive I doubt the SSD will fix my problems.
Could the CPU or motherboard be causing this problem but still pass every stress test that I throw at it? Unfortunately I can't find any cheap X58 boards to buy. The benchmark scores seem to be normal and where they should be.
CPU is at 3507 MHz and the ram is at 1336 MHz.
Cinebench 10 = 20264 multithread and 4938 single thread.
Cinebench 11.5 = 6.02 multithread and 1.19 singe thread.
The frustrating thing is that this PC hasn't blue screened or frozen since I have been experiencing these problems. Zero WHEA errors as well. I just don't get it. Please help before I just give up and find a new hobby.