Won't reboot after memory install/upgrade

[biosol]

Hello,
I picked up a motherboard (ECS PT800CE-A), CPU (Celeron-D 2.66Ghz 533FSB), and RAM (with the rest of the components) and built the computer. After getting up and running for a day, I noticed the store had given me the wrong DDR chip. They gave me a Cosair DDR226 512MB chip and I had purchased a Mushkin DDR400 512MB chip. The BIOS was running at 133x20 at that point. I took the 226 back and got the DDR400 chip, installed it and rebooted. I noticed that the BIOS was still listing the settings at 133mhz x 20 = 2.66Ghz. I checked the and reinstalled the DDR module. Then rebooted and entered the BIOS as the settings were still the same. I tried setting the CPU clock (FSB) to 200 (from 133) in the BIOS but it wouldn't accept it. So I powered down and moved the DDR chip from the first to second slot. Then rebooted and enter the BIOS to set the "fail safe defaults" hoping it would redetect everything, but it now doesn't reboot at all. Nothing... Can someone help me with this. The store said it was single channel DDR, so I thought one DDR chip would work, is that not the case??

Oh, also I took the DDR400 chip out and tried to boot and it started beeping. Could the memory have been DOA?

Please help, thanks,

RH

 

[micker377]

Is there a "jumper" on the motherboard to reset the bios? If not, pull the cmos battery and let it set for an hour. Put the battery back in and reset all the bios settings.

 

[biosol]

Thanks for the reply. Actually, after researching most of the night I got up the courage to reset the CMOS using the jumpers and it's back up and running.

Thanks!

 

[micker377]

Never be afraid to reset that jumper. Just write down all your settings when it IS running correctly, so you can reset it wnen necessary.

 

[paparazi]

biosol
Celeron D has a 533 front side bus so 133 is the correct jumper setting for this chip!

Quad pumped: 4 x 133= 533 approx correct!!

So there will be no differance in settings between the two unless you are overclocking.
Martin

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Participate and help others.

 

[biosol]

Thanks guys. With the 133 x 4 = 533, so does that mean that there are essentially 2 multipliers now? And it seems like the rest of the components still run at 133 (except the cpu and ram). Is that correct?

RH

 

[teknikal]

biosol

I think what you have to do is throw out this term "multiplier". Intel's quad-pumped frontside bus doesn't rely on a motherboard BIOS setting. It all happens internally. Data in the newer bus is sent on both the upside and downside of each clock cycle. Right there, that's "double-pumped" and that's how DDR SDRAM works.

Intel's quad-pumped bus goes one step further. It doubles the amount of data on the upside and downside of each cycle - which makes it 4 times the amount of a regular single-pumped FSB (like you see in the old Pentium III's).

It looks as if you are trying to get your DDR400 chip to run at 400MHz. For that to happen, you've got to adjust the FSB:Memory ratio in the BIOS. Using a 2:3 ratio ought to do it. By default, this ratio is set to 1:1 which is why your 400MHz chip was running at 266MHz (in synch with your FSB - 133MHz x 2). Adjusting it to 2:3 makes the memory bus run 1.5 times faster at 199.5MHz x 2 = 399MHz, while keeping your FSB at the safe 133MHz x4 = 533MHz.

Running the FSB and the Memory bus out of synch may or may not improve performance. Run some benchmarks to find out. You might find that the 1:1 ratio is most efficient. In order to really make use of a DDR400 chip, you should be using a processor that supports a 200MHz FSB.

 

[biosol]

Ok that makes sense. The main reason I got the DDR400 chip is that is was on sale (after rebate = $59) and I usually build a new machine with a current mid level chip, so that when the current top of the lines come down in price below $100 then I upgrade the chip. So it looks like I'm set to upgrade to a P4 800Mhz chip later.

Thanks for all the info,
RH