New CPU Problem

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.
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  1. Relax.
    Hyperthreading will show 2 CPU's in Device Manager.
  2. Id consider that an unexpected bonus..

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  3. 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 to recheck your processor speeds.

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  4. 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!
  5. You are running in cerery mode, change the fsb to 200.
  6. The bus speed only goes to 800 if you have 2 memory chips installed. Do you?
  7. 2 memory chips, why that?
  8. 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.

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  9. Did you try to clear your CMOS?

    PIV 2.8 @ 3.37, 2X256 Geil Platinum PC4000 @ 1:1, 240fsb, SP-94 with 92mm Tornado, IC7, (2)Raptors in raid 0, BFG5900nu flashed to 5950ultra bios, 500 watt psu.
  10. 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.
  11. Hi,

    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.

  12. As the poster above stated.

    Your memory will not run at 200fsb. Your memory is rated for 100fsb.

    You will either have to set the memory at a lower speed in the bios or replace your memory with at leasr PC3200 or PC3500 reccomended.

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  13. 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.
  14. I think a few people noticed this but let me make myself clear:
    HE HAS PC 1600 RAM (100MHZ) The 1.6 P4 used PC1600 RAM)
  15. Quote:
    Maybe my 512 K of PC2100 is too slow?

    Hes runnin on PC2100 so he could run it with 133mhz FSB with a memory/cpu ratio of 3/2. Cpu hes runnin at 200mhz and the ram at 133mhz...

    Now your computer will be faster but still slower than what you would get with DDR400 in dual channel. I suggest you buy a pair of 2X256 meg of DDR400 that would help a lot.

    Asus P4P800DX, P4C 2.6ghz@3.25ghz, 2X512 OCZ PC4000 3-3-3-8, Leadtek FX5900@450/875, 2X30gig Raid0
  16. 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?
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