Well, thats not going to help.

Might make you feel better, but lets hope you don't get any tearing there either.

12v line low - bingo. You're under about 65% cpu load in bios at the moment. Crank that up to 100% and run something graphics intensive and your 12v line is likely going to be overloaded.

My money is on the power supply. Id steer clear of thermaltake as its cheap and made in the far east under licence (by the same factory that makes QTec budget PSUs if anyones interested).

If you're going for a multi rail PSU you will need at least 800 watts with a quad core mate. Your nvidia board pull about 30 watts more than the equivalent intel as well, plus is jammed with extras. If you choose a single rail PSU (corsair TX, PS Power and Cooling, Silverstone OP range) you'll need at least 700 watts to be confortable, but a 650 would cut it (but being at the limit youd be talking PSU fan speed high which is fairly invasive.

Id specify exactly which power supply you want. My personal choice would be the PC Power and Cooling 750watt if money was no object and you can find one. More realistically the Corsair 750TX or Silverstone OP750 will do the job just fine for around £80 - £100. The thermaltake can be had for about £50 if you know where to look. Sounds like you had the spec dropped to make them a few extra quid mate as the 1000watter is made by Antec and costs circa £100.

I'd look to confirm it before screaming blue murder by removing a graphics card and checking for tearing. Don't suppose you have a spare psu of epic proportions to try?

Regards memory, its fine mate honestly. Id look to reduce the speed to 533mhz though mate and change the timings to 4-4-4-12, you'll get better perfomance with the memory and fsb in sync (I know the 680 chipset has an unlocked memory bus, but 1:1 is still quickest) and lower timings (latency). Either that or set your memory speed to 667 and your fsb to 333. Your cpu should do this without changing any voltages at all. If you want to play with tweaking the memory you are safe setting anything up to 2.0vdimm for 24/7 use. I'd set it straight to 2.0v and work your way up from 266mhz fsb 1:1 memory ratio and 4-4-4-12 timings. See how far you get going up in 10mhz fsb steps, leave all other voltages alone. You may be pleasantly surprised as most of the G0 stepping Q6600's do 3.2ghz on the stock cooler with no settings changes apart from changing fsb .

Good job you're not helping me out cos I didnt get any of that last bit.

Like anything with PC's - if you don't understand it google it until you do or don't touch it at all. I never subscribed to that, I learnt how to do everything through breaking it and fixing it again .

In practice its much easier than it sounds. Lowering memory timings decreases memory latency therefore increasing bandwidth. Increasing memory speed increases memory bandwidth.
His processor (fsb) runs at 266mhz.
His memory runs at 333mhz at 5-5-5-15 timings (I think!) and 1.8v.
This difference between fsb and memory speed reduces performance - you gain from higher speed but lose from the memory multiplier, overall you only make a small gain.

My solution would be to reduce memory speed to 266mhz so theres no memory multiplier and reduce latency to 4-4-4-12 timings. You could then set vdimm to 2.0v from the default 1.8v and overclock the whole thing. 333mhz fsb should be easily achieveable without altering anything except vdimm.

Like I said, harder to explain than to show .

Guys I cant thank you enough- We seem to have a partial winner! With a few probs I must admit (including the psu) still to be sorted. Basically god bless Rivatuner for one thing! Ramming Vsync on in the registry has now rendered most games without tearing. So far i've had success with Stalker, Gears of War, CoD4, and UT3- to some extent. Only the judder problem remains (although only when standing near node areas in Warfare or similar, hmm).
On the whole, though, I am chuffed to bits and dead grateful. Its not something I would have tried, having attempted to lock Vsync on at driver level (bloody Nvidia drivers) and thinking it just hadn't worked. One thing Rivatuner doesnt seem to want to do is display my other gfx card- I know im not alone here; i mentioned the guy who couldnt control both his fan speeds, now thats me:( After upping my fan speed on the main gpu to 75% the core temp dropped from nearing 70 to around 62 (after a long gaming session) Is full fan speed was a good idea with this voltage issue? Also anyone know of any other tweaker that will def display both cards? I've tried updating rivatuner but the updates a nono in the paranoid world of Vista64.
As for timings and overclocking- after playing around with Bios's and breaking a few machines I know the basics, nowhere near as confident as Pilsy here though. From what I can tell the Bios has some pretty nice features too. I clocked my last AMD64 up a couple of steps as I fitted another heatsink but u say the standard quadcore ones will take some overclocking? All makes alot more sense to me when Im in the Bios, so im going to take some notes from what u said and go take a look-see!
Thanks again guys, now to test it on TF2!

No problem mate - happy to help.

You can try atitool - its another video card tool and works with both nvidia and ati, though i'm not as well versed in it as ive always used rivatuner in the past.

Juddering could be mouse input problems khola. Does it judder when you're looking around or when you're still as well?

The standard quad core heatsink is ok to about 3ghz on the older quad core chips and about 3.2ghz on the newer G0 energy efficient stepping. Either way 333mhz fsb should be no challenge at all and give you a good boost. Remember you'll be pushing your power supply even harder so if you hit problems don't automatically assume you've gone as far as you can with your cpu/ram/motherboard. Im stuck at 3.5ghz with my dual core at the moment because I get power supply related hardreboots at over 500mhz FSB (I know - mental huh? running my crucial 533mhz ram at 1000mhz ).

Assuming you do get stable at 333mhz khola i'd then start reducing your vdimm one notch every 48 hours. When you get a crash up it to where it was previously stable and you've found your minimum memory voltage to run at that speed. More volts = more heat, so less volts is better. If your board lets you reduce cpu voltage i'd give that a go after you've stabilised the memory voltage. If you can drop that a notch or two it really helps temperatures. If you haven't got that option in bios I have a program that can change multiplier and cpu voltage from in windows .

Matt.

hey matt.. The 'judder' that happens doesnt seem mouse related and only happens in these node-like areas in UT3. At first i thought it was the graphical effect from the nodes but then i went to an inactive node and same thing happened. I have just recently aquired a lazer mouse so i will try my old optical and see if theres any difference- but i fear this is something slightly more sinister. As i mentioned the rest of the game is great and looks and runs like a dream now the refresh rate is sorted, but is rendered totally unplayable at those points. Unfortunately UT3 is so totally lacking in graphic options it's a joke. A slider for texture detail, one for amount of screen to render and I think one for actor detail or similar; along with a preferance for Post processing intensity, Vsync and a recently patched in Frame smoothing option. Really not alot for a game so advanced. Not even the DX10 option its cousin Gears of War sports.
As for your overclocking results, well done mate! 3.5ghz a core? What model core2 did u start with?! and its crazy your running your mem at 500x2! Damn nice machine by the sound of it and looks like you've squeezed every ounce of power you can out of it! Much more efficient than a machine like mine.
Only thing bugging me atm is on running the Valve survey it didnt detect my Sli and the fact that Rivatuner doesnt want to see it. Although when I run the Sli indication bars from the driver in games it does seem to be acting differently top and bottom.
Anyway dude thanks again for your continuing support, really. No doubt I'll bother you again as i decide to overclock
(oh and the chip has GO stepping, im pretty sure)

Dan,

An E6750 mate. Running it a tadge under volted as well from stock - it came at 1.372v and im currently running it at 1.340v, so well happy. I know its my power supply buggering me up as if I increase processor voltage I get reboots until I drop the speed. Figured out it can handle 113 watts from the cpu, whether thats low speed high volts or high volts low speed doesnt matter. Thats my lot! Just can't be bothered spending a ton on a power supply when to be honest this pc mullers anything I throw at it anyway.

I would blame that drop in performance on vista 64 mate. If you have a second hdd stick XP pro on it and test that. If you need a second hard disk pm me - I have spares and can donate .

Thinking about it the SLI not being detected thing could be vista 64 too maybe? Not necessarily driver support, but probably game support to recognise the driver?

Nice mate thats an awesome chip... will be nice if i can clock mine up a tad so anything using 1 core will run at more than 2.4ghz... im still none the wiser about when the machine actually decides to use all its cores. The whole multi-core experience is a little new to me, my last machine using an old 754pin AMD64-3000 (2.0ghz clocked to 2.2).

As for Vista64 i've heard that a bunch of people on the Crysis-sector forums have got between 10-30fps extra from just 'downgrading' to Vista32. Though atm every game apart from UT3 and Crysis runs very fast indeed, though I guess it would with one GTX.

Anyway I'll keep tweaking, as ever, and if it's cool pop back for advice. I've always enjoyed discussing PC's even when mines been a heap! (you should see the state of my last PC- might actually paste a pic up it's such a joke! No side panels and more dust than an antique shop!)

Oh and I have XP installed on my internet machine here- maybe i should just wipe some drivers and whack it in the new rig?

Anyhows... early night to be had and plenty of games to play 2mrw!

Anything as mental as this? Its a fair few years old but i've not had a camera for ages so got nothing current...