First off, I'm very new to overclocking, so I'm not entirely sure of all that's involved. I have an Intel q9550 with a gigabyte ep45-ud3p mobo. I decided to experiment with a modest overclock, going from 2.83 Ghz to 3 Ghz. After a bit of research I thought that all I would need to do would be to change the FSB. I assumed the CPU could handle that small of an increase on the stock voltage. I changed the FSB from 333 to 353 in the BIOS with the same 8.5x multiplier. Though after I saved and rebooted, Windows wouldn't start. I'm dual booting the Windows 7 RC and XP, and neither would boot up. I switched back to the default FSB, and it starts just fine once again. I know that the temperature should be fine, as my CPU idles at about 29C, and reaches the mid 50s under load at the default settings. I have two sticks of 2GB DDR2 1066, which I believe should also be able to handle the increase. The Windows boot loader gave an option to do a repair boot of some sort citing hardware changes, but that didn't work. I'm left wondering what the problem is.
Leave the FSB alone if you don't know what you are doing.
The only thing you should make sure of is that if your RAM is 1066Mhz then change the frequency to 1066 but you also need to change the timing to get a stable system...
The BIOS doesn't give me the option to change the RAM frequency by itself, but I can change the system memory multiplier. I changed it to the nearest option that wouldn't go over 1066, which puts it at 847Mhz. Windows now starts, but will that be satisfactory? Timing control is on auto, and is currently set at 5-5-5-15.
You need to do a lot more reading up on overclocking if you cannot work through this problem, as the problem you are having is like....well it's like if you are going to learn how to drive, but you don't even understand how to get the car started.
You should also go back and read your motherboard manual, very closely and carefully.
You need to set your RAM down to 800mhz before you start messing with the bus.
Yes, RAM is usually very sensitive, and will not stand much overclocking at all, and is the first thing to cause your overclock to fail.
ep45ud3p motherboard is a very simple overclock, and I know exactly what your problem(s) are because I have the same board. Now I know this thread is old, but it may help future would be overclockers. First, take your timings off of auto, the auto always screws it up, manually set the basic timings to what you see to the left, as those are the factory settings for your ram. If it says 5 5 5 15 on the left, manually put in 5 5 5 15. On a simple overclock with 800mhz ram I can reach 3.2ghz (up from 2.66ghz) at a 8x multiplier, with 1066mhz ram I have gotten 4.0ghz at 8x multiplier without voltage increase, and 4.36ghz with a slight voltage increase and a slight ram overclock.
Now #1: manually set your timings to factory for eas overclocks, don't mess with these unless your very experienced.
#2: go gown and set ALL of your voltages to "normal" not the number, it will actually say normal, if you leave it on auto it will be a no go.
#3: set your multiplier to 8x (it will be easier to be explained this way on my instructions, you can mess around with it late)
#4: go and set you frequency (fsb) to 400, yes on this board the only things you really mess with for simple overclocks is the multiplier, frequency (fsb), and memory multiplier, and they are all very easy.
#5: by setting your frequency to 400 it will bu,p your cpu well up, with mine it bumped from 2.66 to 3.20, but it also bumps the ram up, so go down and scroll through the options using the page u[ and page down keys until your ram frequency is either at or below what it is rated for. escape, save and exit and it should boot just fine.
The great thing about the ep45ud3p boards is the dual bios, which means if you screw up you don't have to sit there and reset cmos, pull the battery or anything, just let it shut itself off, and restart and everything is reset to default.
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. Then when you increase the FSB, the memory clock will rise in in proportion with it. 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.
Warning - confusion factor between what the BIOS calls things and what CPUZ calls things. What the BIOS calls "memory frequency" is actually the memory clock. What CPUZ calls "memory frequency" is half the memory clock - DDR2 RAM, remember? One bus cycle generates 2 memory clock cycles. What you want in CPUZ is a 1:1 FSB:RAM ratio. You gain very little real world performance running the memory faster than the FSB freq in a Core2 system. Overclocking memory doesn't accomplish much besides limiting your CPU overclock where the real speed comes from and increasing instability. One place we discuss that: http://www.tomshardware.com/forum/251715-29-ratio-myth
For a serious overclock, you will need better than stock cooling.
I have a Q9550 (C3 stepping ) in a GA-EP45-UD3P OC'd to 3.6 GHz. It is 24 hour Prime95 (both small fft's and blend) stable. ----------
Overclocking since 1978 - Z80 (TRS-80) from 1.77 MHz to 2.01 MHz