X48-DS5, Q9550, 2xHD4870X2s - Overclocking advice please

[samuelmorris]

Hi there, rather than bump any several-month-old threads, I thought I'd post a fresh new topic.
I'm using an E0 stepping Q9550 with the above, and my overclocking ability is, disappointing, to say the least.
I used to own an X38-DS4 and ran at 430*8.5 = 3.65Ghz on a 24/7 basis with no stability issues and could push to the 455FSB wall of the X38 chipset, and at least manage benchmark runs, though the overall stability was questionable. The reason I upgraded to the X48-DS5 was that when I purchased the second HD4870X2 card, I would get GPU shutdowns in games - i.e. graphics fans rise to half speed, monitor goes into standby, and system has to be reset manually, this regardless of my CPU overclock.

After getting the DS5, this still happens whenever the system is overclocked (but not at stock), unless I set the G(MCH) voltage to exactly +0.1V. Leave it on auto and the black screens return, raise it any higher and the black screens return. As a precaution I have also raised the PCIe voltage by 0.1V.
If anyone could explain this I would be very grateful, ATI insist it's a PSU issue but the fact it happens with a BeQuiet DarkPower Pro 850W, Zalman ZM850-HP AND

[Nickel020]

Re: X48-DS5, Q9550, 2xHD4870X2s - Overclocking advice please

I ahve no Crossfire experience, but please try to overclock with just one card, to see if that improves the situation. We need to single out the problem and to know whether CF has something to do with it is important.

The X38 and X48 chipsets are virtually identical btw and and so is the EX 38 (but not the X38) and X48 series.

[samuelmorris]

[samuelmorris]

Re: X48-DS5, Q9550, 2xHD4870X2s - Overclocking advice please

Hi Nickel, thanks for the response, while I admit CF could be a problem when in windows, the fact is, it activates when the Windows logon screen appears, until then it's just two separate cards as far as the system is concerned, and it's pre-windows that the stability issues pop up. With just one card, I could get 3.87, but no further, using the aforementioned settings but +0.1V on the MCH, and not having changed the Skew controls.

[Nickel020]

Re: X48-DS5, Q9550, 2xHD4870X2s - Overclocking advice please

Glad it works!

Ok, the fact that a fan on the NB helps indicates that CF causes more strain on the NB and it overheated. That's why more than +0.1V MCH Core caused it to become unstable according to your first post. Maybe get a small 40mm fan and put it on the NB, teh 4870X2s are so loud you likely won't notice it anyway.

I don't have any experience with the following two:

CPU/PCIEX Clock Driving control: 800mV
CPU Clock Skew Control: 100ps

CPU clock skew is supposed to help though according to clunk.org.uk
What is the dault value for CPU/PCIEX Clock Driving control on you board? On P45 it seems to be 900mV...
Gigabyte GA-EP45-UD3R Living Review - Clunk's Forums.

I don't really know what it does though, you should do some research as to what it actually is.

[samuelmorris]

Re: X48-DS5, Q9550, 2xHD4870X2s - Overclocking advice please

Indeed, the clock skews still mystify me as I don't know if they're actually helping, I just copied them from a guy who got an X48-DQ6 to 4Ghz with my CPU (but he used +0.475V on the chipset, which is a bit rich for my taste)
I've also no idea how to find out what the defaults are, it's hard enough working out what the defaults are for voltage.

I tried to get to 470FSB, and raised the MCH volts to +0.35, not only was I met with a bluescreen (101, but hardly relevant, as its obvious what caused it), but also the blackscreens came back, even with the full speed side fan.
I've come to think that the only way of pulling 4Ghz off on this board is indeed to use the insane voltage this guy at overclock.net used. In addition, he only used a single 8800GT, not two dual-GPU cards.
As much as I want to put a fan on the NB, the extra cooling is needed every bit as much at idle as it is at load - and I do care about idle noise. My PSU and GPUs are very quiet at idle, a 40mm fan on the chipset would ruin that.

[Nickel020]

Re: X48-DS5, Q9550, 2xHD4870X2s - Overclocking advice please

You could try to get rid of the heatpipe and get a Thermalright HR05 for the NB and a HR09 /chekc the compatability list on their website!) for the mosfets. The SB will be allright with any low profile chipset heatsink.

Or try to undervolt a 40mm fan, even a little airflow may greatly help.

[samuelmorris]

Re: X48-DS5, Q9550, 2xHD4870X2s - Overclocking advice please

Thermalright's site is a bit confusing about that - it lists the HR-05/IFX, SLI/IFX being compatible with both the north and southbridge, but just says 'not compatible' with regard to VRMs with the comment 'you need to remove stock heat pipe' - does that refer to the chipset, or does that mean you can use an HR-09 if you take the whole Gigabyte assembly off (which should surely be obvious)?

I could indeed try undervolting the fan, but I'm not sure it'll do that much good on the basis that even the 2400rpm 120mm side fan isn't enough once I push past +0.3V.

[Nickel020]

Re: X48-DS5, Q9550, 2xHD4870X2s - Overclocking advice please

Actually the first thing you should do is remove the heatpipe, clean the NB and apply some proper thermal paste to it, that can improve NB temps greatly.

The "you need to remove stock heatpipe" disclaimer refers to the fact that you need to remove the ehatpipe to change any one cooler.
I just noticed that there is no HR09 for your board, I thought they had one...

Watercooling may be an option, there are plenty of blocks for X48 mosfets out there, but a CPU, NB and Mosfet solution isn't all that cheap.

You can also cut the heatpipe and change only the NB cooler, but you're unlikely to be able to RMA the board after that...

[samuelmorris]

[Nickel020]

Re: X48-DS5, Q9550, 2xHD4870X2s - Overclocking advice please

Try the undervolted 40mm dan though. A fan that is quite far away like your 120mm doesn't actually provide much airflow through the tight cooling fins of the NB heatsink, a small fan strapped directly on it is much better even if it is very slow.
Coming from watercooling I know that a very slow fan can make a huge difference. Even 400 rpm 120mm greatly increase the cooling performance compared to now fan at all on a watercooling radiator (which is nothing different than a heatsink cooling water basically).

[samuelmorris]

Re: X48-DS5, Q9550, 2xHD4870X2s - Overclocking advice please

Very true, and running my CPU passively is the same result. I'll try and get hold of one, thanks for the help so far.

[NimrodAUS]

Re: X48-DS5, Q9550, 2xHD4870X2s - Overclocking advice please

Yeah I found that if you pull off that Silent pipe badge on the top of the NB It will help. But a 40mm Fan undervolted to the shiit house will keep the temps way way down. But I think that if you have these problems then you shouldnt be runnin it that hard. Have you tried just +.1Volts on all that stuff and see if that works? I have mine running at 3.8 stable and it probably doesnt even need anything over stock except the CPU to 1.3v but ur CPU is different so I dont know, but yeah. Whats your PCI express Freq? 102Mhz?

[NimrodAUS]

Re: X48-DS5, Q9550, 2xHD4870X2s - Overclocking advice please

Yeah as Nickel020 says it only needs a real slow rpm 40mm fan on that NB to make a world off difference, there is a NB fan header and also the other PWR fan header on the board so there are plenty of spots. Just get some of those plastic screws and screw it straight to the fins on top and its sweet. Wish Gigabyte would provide one with the board or atleast sell one themselves that was ready to go.

[samuelmorris]

Re: X48-DS5, Q9550, 2xHD4870X2s - Overclocking advice please

I have two 5.25" bay fan controllers, so am in no short supply of places to plug fans in. It's certainly temp related, as up to a point, the faster a side case fan I use, the further I can go with the NB voltage. As I mentioned before, I like my system super-quiet at idle, and since the problem is still a factor at idle (presumably because idle power consumption of a chipset doesn't drop that much from load) I need a quiet solution to the problem. I will, when I acquire one, try a 40mm fan attched to the chipset, and I've also always wondered how detrimental those fancy nameplates on heatsinks are.
Using +0.1 on the NB is the sweet spot, Auto or anything higher requires more cooling, and I don't think any lower voltage is stable at my speed (3.65).
If there's one thing I've learned from my research, there are three things that reduce how far you can overclock with a modern chipset:
1. Using X48 vs P45 - Check. (Though I read an astonishing review on just how much better X48 is over P45 for crossfire performance, so using, say an EP45-UD3P is out)
2. Using a Quad core - Check. Dual cores like your E8500 are a doddle to get to 4 gig on just about any board.
3. Using two graphics cards - Check. Two 4870X2s? When you run 2560x1600 like I do and like your eye candy, you'll understand :)

My PCI-E Frequency is the stock 100, I've nevr really understood the gains of overclocking it.

What I have done for now is placed an old Minebea 4000rpm 92mm fan directly on top of the upper graphics card with the direction pointing upwards brushing past the northbridge cooler, into the CPU cooler. (A 4000rpm fan? I scavenged it from an old Compaq system I upgraded - couldn't get the fan speed controller working on the new board I bought for it - so it ran at full speed. Ouch! I therefore bought an Xilence redwing for it instead)
I encountered a blackscreen yesterday even at 3.65 when using my case side fan at minimum speed, so I certainly think active cooling on the chipset needs to be an option.
I'm still going to go ahead and replace the thermal gunk on the board at some point, but it's a lot of hassle, so this will have to do for now.