Hello again,

You may remeber yesterday I posted a thread on upgrading the CPU on a Dell XPS 720 machine from an Intel Quad Core Q6600 2.4 GHz 65nm 1066 FSB chip to an Intel Core Extreme QX9650 3 GHz 45nm 1333 FSB (or alternatively a QX6850 3 GHz 65 nm 1333 FSB). All of these use an LGA775 socket.
My motherboard is one made by Dell which came with the machine, an XPS 720 for those of you familiar with it, and is described by CPU-Z as:
Manufacturer Dell Inc., Model 0P611C, NVIDIA nForce 680i SLI SPP Chipset, NVIDIA nForce 680i SLI MCP Southbridge, SMSC for LPCIA. The BIOS is also by Dell, version A05 dated 01/03/2008, so the most recent, I guess. Graphic interfact is PCI-Express, with link width x16, also max supported.

You guys are a goldmine of excellent advice and information, and I don't want to get this CPU change wrong, so if you could advise whether this motherboard will take the QX9650 or QX6850 I would be extremely grateful! Thank you for your advice so far on the previous thread!
Best regards,
AJS

QX9650 = win, it will overclock better, and perform marginally better generally. How much is the price gap between them from wherever you are buying them from?

Hi, at amazon.com they are sold both for essentially the same price, the cheapest being in the region of 900 US dollars, or 450 UK pounds. So if the QX9650 is better I would certainly go for it, the question is whether my motherboard will support it properly .

Dell have yet to release a BIOS for the 720 that will support the 45nm CPUs. They WILL NOT WORK in the 720 or the 720H2C. They have even stated they have no intention of updating the BIOS for 45nm support.

Some of the earlier 720 boards don't even like running at a 1333MT/s FSB as needed by the QX6850.

This is not a worthwhile upgrade anyway, you really won't see much of a performance boost in games, considering the $1000 you are talking about spending.

I have a 720H2C myself, although it is not on its original CPU or GPUs, which I currently use as a fileserver and media centre PC. The BTX motherboard in these is utter crap to be honest

I bought the 720 only 2 weeks ago or so, so the motherboard should be the newest they have, right?
In this case the QX6850 would be a safer choice, it appears.
I don't really run games on my machine, I need it to do ABAQUS finite element simulations among other, for which do need a fast processor, and I think the 0.6 GHz (or more if I overclock it) boost could be worthwhile.

Yeah, Just OC ur Q6600 to 3ghz... cheap and basicaly the same.

I tried that, but the OC is locked in the Dell BIOS that it came with. I tried the nVidia nTune application, and I got it to 2.7, but the system became unstable and crashed all the time, restarted all of a sudden etc. etc. etc. maybe I did something wrong? Is this a reliable way of overclocking?

You have said in your other thread that you have issues overclocking. Alot of these boards suffer from the same FSB issue with quad cores as the original reference nVidia 680i boards did - only dell never bothered fixing it.

If your board is affected by this it would explain you struggling to overclock.

A better choice would be the QX6800, which, while older, will definitely work and can still be overclocked by the BIOS as it has an unlocked multiplier.

An even better, and even cheaper, option would be to buy a new case and motherboard, throw the crappy dell motherboard away, and overclock your Q6600.

You'd probably get more performance, and it would certainly be cheaper, to take the 2nd option.

Hi Darkstar782,

So the Q6600 is automatically locked in the BIOS, and the QX6800 is not?
This would be cheaper.
I would love to change the motherboard, but I don't really want to throw the computer case away because it's quite nice, actually. I wouldn't feel confident enough to change a whole motherboard myself.

You can switch the mobo without chucking the case, can't you?

sell the Q6600 as 2.4ghz only, or try it in your new mobo.

then think about your CPU again.

Correct. Dell lock the FSB and Memory clock. If the CPU has an unlocked multiplier it allows adjustment of the multiplier. It is a very blunt instrument however and makes up its own vCore. This is how the 720H2Cs are overclocked - multiplier adjustment.

No, the XPS720 is a BTX only case. There are no decent BTX motherboards available to replace it with. The point of changing the case would be for an ATX design.

Not worth the $1000.

Bear in mind that if you do want to overclock you are going to need a better cooler than the stock one in the XPS720 (unless yours is a H2C, but it can't be as those don't come with Q6600s), and most decent coolers will require you to remove the motherboard from the case to fit the retention system.

Definitely get aftermarket cooling (in case you are still using the stock cooler), a new motherboard, and even a new case if necessary.

ARE YOU SURE ABOUT IT BEING A BTX ONLY CASE :|




Odd decision by Dell.

Yes I'm sure, I have one.

Dell do what they want, their custom 680i board is BTX so the case is BTX. They are not interested in making it easy to upgrade.

Can't you remove the mobo tray or make ANY adjustments ATALL? To allow an ATX case?

Hm... I swear the next machine I get will be custom built.
I won't be able to change the motherboard.
Darkstar, tell me since you have the machine, is it actually physiacally possible to remove the motherboard and change the processor? Is this difficult or troublesome? I notice there is a huge fan in the way, is it possible to just remove the fan/cooling thing, keep the motherboard inside the machine, and change it that way (if I decide to do it)?

I don't think they would leave the motherboard permanently attached to the case, however the problem is that Dell and most OEMs use a BTX form factor on their boards and cases, but most if not all of the decent boards out there are ATX, and creates a problem when attaching it to your case, all of your other components are fine though.

This is why what we suggest the best thing to do is to lose the dell case and board and get something along the lines of a GA-P35-DS3L ($90-100), Antec Nine Hundred ($100-120), and maybe even a CPU cooler like the ZeroTherm Nirvana ($45) which should allow you to overclock that CPU just fine. If you ask me that's the best course of action and price shouldn't be a problem, since you were considering to pay $1000 for a CPU with marginal increase.