Dell 4550 CPU issues

[rivitingone]

So here's the situation. I reciently acuired an old P4 2.8 Ghz Prescott cpu. After checking out the CPU info on dells website and seeing that the bus speeds and clock speeds were listed I dropped it into my Dell 4550, replacing the stock 1.53 Ghz chip. Much to my chagrin however the computer would not so much as post. After doing some digging on numerous forums I discovered that the Prescott is unsupported by the 4550's bios. There was conflicting info as to whether dell locked out the prescott or if it was because that CPU has a 1M L2 Cache and the system is set up for a max of 512k. Regardless, I have now replaced the original CPU but once again I am unable to get the machine to post. The power comes on, the HDD's spin up but there are no beeps and, contrary to what Dell apparently thinks, the 4550 doesn't have diagnostic lights. Both CPU's are good as I can get it to work on another spare machine.

And now, at long last, the questions. Is it possible that installing the Prescott and trying to boot I have some how damaged my motherboard? Is there something I am missing that is making this so much harder than it needs to be?

The only physical difference I can see is that the Prescott would use more power usage and produce more heat. Neither of these should have been an issue with the system however. Both chips are socket 478 and there was no issues while installing/reinstalling either of them.

 

[Eric1]

Well I am not the processor guru but here is a few things to try. Make sure all connectors on the mother board are plugged in and in the right place, take out the little battery on the mother board and then put it back in, also you might have to flash the bios to get it working again.

 

[peterhuang913]

If the Dell is old, it probably won't support prescotts so you need to use regular p4's. I think you should match caches too. When you put the old one in, you should try to reset the BIOS by taking out that little battery on the motherboard, unplugging the PSU, press power button, and let it sit there for a minute or two.

Technical Specifications: Dell Dimension 4550 Series
As it says right there, the processor has to have 256kb or 512kb cache.

 

[KSoD]

You will have to clear the CMOS. That should allow it to boot.