I recently purchased a Q9550 from Microcenter for $150 and have read about many other owners of the Q9550 being able to reach near 4GHz while staying well below 1.4 vcore. I am using a GA-P35-DS3L and am positive that the mobo's FSB can run comfortably at a FSB speed of up to 465 MHz because that is what I ran my old E6750 at (465x8=3.72GHz). Unfortunately, I cannot get anywhere near the great clock speeds other people are reporting with their Q9550's. Even with vcore set to 1.35, my system is not stable running at only 3.2 GHz (that's 380x8.5). The weirdest part about the instability is that unlike my previous overclocking experience with my old E6750, my system does not blue screen under load, but instead simply freezes. So far, the highest stable OC I was able to achieve was 3.145 MHz (370x8.5). Is it possible that this Q9550 simply cannot be pushed very much, or does it sound like there is something else going on? Maybe my PSU isn't powerful enough for the quad core? I'm using a OCZ600SXS power supply. Here are the rest of my system specs (from my xfire page):
Manufacturer: Gigabyte Technology Co., Ltd.
Processor: Intel(R) Core(TM)2 Quad CPU Q9550 @ 2.83GHz (4 CPUs), ~2.8GHz
Memory: 4096MB RAM
Hard Drive: 250 GB Total
Video Card: NVIDIA GeForce GTX 470
Monitor: Samsung SyncMaster T220
Sound Card: Realtek Digital Output (Realtek High Definition Audio)
Speakers/Headphones: Turtle Beach HPA2 Surround Gaming Headset
Keyboard: Standard PS/2 Keyboard
Mouse Surface: Max Payne
Operating System: Windows 7 Home Premium 64-bit (6.1, Build 7600) (7600.win7_gdr.100618-1621)
Computer Case: NZXT M59
Yeah, after some googling I'm starting to think my mobo is to blame for the lack of success in overclocking this processor...I have read about some pencil volt mod that limits vdroop, but I'm not even sure this would help me achieve higher clock speeds.
Yeah my C2Q didn't overclock nearly as well as my C2D did on the same board.
I'm really surprised your 800mhz ram was running at 920mhz. You don't have to do that you know right? You can get the same overclock and run the ram at stock or below by unlinking the cpu from the fsb or by lowering the ratio.
I did reduce the ratio as low as possible but I didn't know there was any type of option to completely "unlink the cpu from the fsb". In fact, was that a typo? If I wanted to not overclock memory and instead just raise the fsb, wouldn't I want to "unlink the memory from the fsb"? As far as I know, this is not possible (at least not on my mobo/processor).
I'm really no expert on the topic, sorry for my being confused.
Go through the guides. Then take your core voltage off Auto and set your memory voltage to factory recommended values. Change the System Memory Multiplier (or whatever your BIOS calls it) from AUTO to 2.00, 2.00B, or 2.00D - whichever you need to set the Memory Frequency to twice the FSB. At an FSB of 333 MHz, your memory clock should be at 667 MHz.
Download CPU-Z to check your FSB:RAM ratio. It should be a 1:1 ratio. This is what will give you room to increase your FSB freq without exceeding your memory limits up to 3.6 GHz.
Gigabyte BIOS doesn't use "linked and unlinked" like eVGA or "straps" like Asus.
If you start having problems as you get close to 3.4 GHz or so, you can tell if it's your memory by setting it to half speed (CPUZ ratio of 2:1). If it doesn't run, your problem is CPU settings. If it runs, your problem is memory settings.
If it looks like you are having memory problems, try increasing memory voltage to a max of 2.2 volts or relaxing the memory timing.
If vdroop is less than about .05 volts, don't worry about it. It's probably not your problem. My EP35 board has a droop of .025 volts at a vcore of 1.425 volts.
And finally, a lot of what you can do will be determined by your CPU's VID. As always, YMMV.