Maximum PC

To start with I'm not sure if my question is more suited for the Overclocking forums or the Free Clinic forums but since my Overclock seems to be causing my issue I'm posting it here.

I'm using the Gigabyte EX58-UD3R motherboard and the Intel i7-920 processor that I've been able to clock to a mostly stable 3.6GHz without too many issues, the reason I say mostly stable is because while the system doesn't crash after a few hours of Prime95, OCCT, and IBT testing it appears to be messing with my USB mouse causing it to disconnect randomly(it will reconnect after a few seconds).

The system is currently clocked at 3.2GHz and the mouse issue seems to have gone away as I've dropped it down to this speed about 2 hours ago without the mouse acting up again. Short of lowering my overclock I haven't seen any settings that have resolved my issue so I'm at a bit of a loss as to what to do here. I'd love to try and push the chip farther but this Mouse issue would have to be resolved first.

Any suggestions?

What are the rest of your system specs?

How are you achieving your overclock? BCLK * Multiplier.

What speed is the RAM running when you overclock? What is it rated for?

What is your QPI running at after OC, and did you lower the multiplier as you increased BCLK?

The rest of my system specs are as follows:

Video Card: Sapphire Toxic HD4870 1GB
RAM: OCZ 6GB(3x2GB) 240-Pin DDR3 SDRAM DDR3 1333 (PC3 10666)(Model: OCZ3X1333LV2G)
Power Supply: PC Power and Cooling S61EPS 610W

I'm achieving it with the BCLK(only think I've found in the BIOS to adjust the speed) with setting of 174x21, the above is what the RAM is rated for from what I've gathered but I'm not entirely sure what it's at at the above clock speeds I'll have to edit that into this post when I get a chance, and the QPI if I'm not mistaken(might be the wrong setting I'm thinking of) was set to Auto but I've also tried x36 as well again I'll edit that in when I get a chance to verify.

Edit: The RAM appeared to have been running at 1396MHz but ended up changing the multiplier so it's now down to 1068MHz, I'm assuming those are the numbers you're looking for if not CPU-Z is reporting a DRAM Frequency of 534MHz.

The QPI numbers were correct.

Is there a lower multiplier available in the QPI menu? Your QPI is likely higher than 6200MT/s which may be a bit much without adding voltage for stability.

This isn't a wireless usb mouse is it? Is it an optical mouse? Are you using it on a reflective surface?

If it's not a mouse defect, and since the problem becomes more intermittent at slower clocks, we can probably narrow the issue to bus speed, voltage, or a faulty controller. Any is as good a place to start as another. A BCLK overclock affects the entire bus which is why the RAM and QPI speeds increase also. Since the USB controller is part of the southbridge, I would consider adding a small amount of voltage to the southbridge chipset through the BIOS if possible.

While troubleshooting, it's best to leave the RAM at its present speed, but if we can figure out the real problem, there's probably no need to run the RAM underclocked.

The QPI multiplier is the lowest it can be, the options I had was Auto, x36, and it only went higher from there. The mouse is the Logitech G5(Wired), the mouse pad is one by Thermaltake(not sure of the model) it's a hard black plastic one and doesn't appear to be very reflective if at all. As for the mouse being defective I did consider that until I attached it to another system with no ill effects after two hours of use(on the OC'd system it might have went 20 minutes before losing connection and then more frequently after that) unless of course the increased bus speeds were bringing out those defects.

With that said I did end up lowering the multiplier on the CPU to 20, bumped the BCLK to 180, and so far I haven't had the mouse lose connection but I will play with the settings again and if it reappears I'll try your suggestions, as of the last 6 hours or so those few tweaks seem to have resolved the issue but I haven't done much of anything overly demanding to know for sure. I'll probably load up a couple games and see what happens over the next couple days and see what happens.

It's not the QPI he has to worry about, It's the Uncore that he needs to make sure it doesn't go over 3200 or instability happens.

for example with my over clock of 3.8 ghz on the exact same motherboard rev 1.6

Bclk 200
CPU Step x19
DDR3 1600 step set at 8
Uncore set at 8
my voltage was set at 1.27 in which it never weny over 1.24
and never adjust the pci-e speed leave that at 100.

I don't want to step on any suggestions here because I'm really a proponent of cultivating participation in this forum, and hopefully growing membership. However, I am confused by the previous post. Uncore is a term appropriated by Intel to encompass functions critical to the core that are no longer performed by the chipset. Among the processes grouped under the term Uncore are L3 cache (not L1 or L2), memory controller, pipeline bus, (in newer tech) the "Thunderbolt" controller, and (the most likely to cause instability to core processes) the QPI.

Any suggestion that the Uncore processes may be the root of system instability should start with observation of the QPI speed.

Which is why you don't wont the uncore going over 3200 max, qpi is really used for cpu to cpu communications as such in a multi processor system. The uncore is used for system communications on the x58 chipset and if you let it go over 3200, system instabilities do result. When I clock it up to 3.8 ghz my qpi on mine is 7200 with no instabilities. If I hadn't adjusted my uncore then it would have been unstable

First of all, I don't think there are two identical silicon parts in the world, so your experiences with a particular part will always be unique.

Secondly, you are using the term "Uncore" improperly...

http://en.wikipedia.org/wiki/Uncore

Uncore is a collection of core processes independent of the chipset.