I just replaced my P4 1.6 with a new 2.8 "C" Gig HT P4 800 mhz CPU and experienced problems from the get go. I think the problem is my Asus P4S800 mb. The support page says it should support this cpu. When i first installed the CPU, win XP Pro hung on boot up and the bios stated that cpu speed was wrong. I removed the cpu, put the old one in again (ran fine) and used EZFlash to Flash the bios to the latest P4S800_7. Reinstalled the 2.8 CPU and now it will boot up ok. BUT... when I go into Device Manger under Processors there are 2 CPU's listed. If I try to uninstall one it reappears on next boot-up. More seriously, when I tried Sisoft Sandra Standard and PCMark2002, both benchmarks confirm that the cpu is only running at 1.4 Gig. I checked the bios again, it says the cpu speed is 2800 (14x multiplier and ext. freq of 200/33). Why is the bios saying one thing but the cpu is actually only at 1.4 Gig (half speed)? And why are 2 prcessors showing up in Device Manager. Do I have to manually change settings or jumpers? nothing in the manual? Any help appreciated. Thanks.
All "C" processors have Hyper Threading, which allows your computer to run two separate program threads simultaniously, making use of parts of the CPU for one program that might sit idle for the other. In order to function, XP sees 2 processors.
Now, I'd download CPU-Z from wcpuid.com to recheck your processor speeds.
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I ran several new benchmarks including CPU-Z. The results are:core speed 1400 Mhz, Multiplier x14, fsb 100 Mhz, Bus speed 400 Mhz.
Any idea why my fsb is at 100. Also, the BUS speed is supposed to be 800 isn't it? Help!
eh? where'd you get that idea from? The bus speed has nothing to do with the number of occupied RAM slots.
You need 2 sticks to take advantage of Dual channel, which means the actual bandwidth of the RAM will match what the processor can utilize, but it doesn't change the actual Mhz of anything, it's just a symptom of the P4's QDR(4x) bus and combining it with DDR(2x) RAM at the same actual frequency.
you need to go into BIOS at bootup and set your Front Side Bus (FSB) - it might be called 'External Frequency' or similar - to <b>200</b>Mhz.
If you still have problems, most likely your RAM is not fast enough - it needs to be PC3200 (DDR400 / 200Mhz) rated to cope. if this is the case you might be able to set the bios to run the RAM at 50% of the FSB speed. this should be covered in your motherboard manual - the sections covering the BIOS are usually near the end.
I checked the bios - the cpu external freq is already set at 200/33. However, CPU-Z and System Info indicate that FSB is really only 100 Mhz. Why the difference? I also, cleared the CMOS - no change.
Any time I go into the bios and change the cpu ext. freq. settings to a higher level and reboot - the system hangs trying to start XP. ANY changes to the bios make the system unstable. Maybe my 512 K of PC2100 is too slow? Any other ideas on why my bus is at 100 when the bios says 200? Thanks for your help.
Seems you are unable to Hyper Thread at full speed. the system automatically throttles back 50% and restart.
which gives you the 1.4Ghz and shows up as 2 processors.
proper HT should give you 2x2.8 Ghz
Dont know why this happens, but try to disable HT in the bios, then you get 1 processor running 2.8
Drop me a line if this helps.
It is posssible that your chip is throttling due to temps. Boot your system, and go into bios. Go to the screen that shows chip temps and leave it there for 10 minutes or so. If your temps are around 75c/ 167f, you are throttling. Problem is probably a poorly installed hsf.
Yes well he has pc2100 ram, and the sis chipset board will auto detect and set timings accordingly. With pc2100 his system would default to 133/533 fsb if mem were contoling fsb. This is not the case, so the problem lays elsewhere. Has it ever hurt to make sure temps are ok?