# Replacing an AMD Athlon processor ? **URL:** \ **Category:** Factual Questions\ **Created:** [June 21, 2005, 6:31pm UTC](https://boards.straightdope.com/t/replacing-an-amd-athlon-processor/309232 "2005-06-21T18:31:58Z")\ **Posts on this page:** 18\ **Page:** 1
**Author:** ![simple\_homer](https://avatars.discourse-cdn.com/v4/letter/s/9de0a6/32.png) [@simple\_homer](https://boards.straightdope.com/u/simple_homer)\ **Post date:** [June 21, 2005, 6:31pm UTC](https://boards.straightdope.com/t/replacing-an-amd-athlon-processor/309232/1 "2005-06-21T18:31:58Z")
The processor in my computer died due to overheating when the cpu fan stopped working. The original processor was a one gig AMD Athlon (thunderbird ?) I am in the Philippines, and there are no AMD processors available for sell here, so when a buddy of mine returned to the states he picked up a used processor for me that was marked by the seller as 900 MHZ. Now that the processor is installed, WIN XP is telling me that the speed is only 500 MHZ. The computer is a powerspec 7805 with a Gigabyte GA-7ZMM motherboard. Are there some changes I need to make in order for the processor to run at the 900 mhz ? Here is what the powerspec website says about the motherboard. [http://www.powerspec.com/systems/archives/system\_components.phtml?component=328&selection=7805](http://www.powerspec.com/systems/archives/system_components.phtml?component=328&selection=7805) Or did i just get stuck with a 500 MHZ processor ? Thanks ! ---
**Author:** ![Fringe](https://avatars.discourse-cdn.com/v4/letter/f/b5a626/32.png) [@Fringe](https://boards.straightdope.com/u/Fringe)\ **Post date:** [June 21, 2005, 6:41pm UTC](https://boards.straightdope.com/t/replacing-an-amd-athlon-processor/309232/2 "2005-06-21T18:41:49Z")
I’m afraid I can’t give too specific of instructions, as I’m not familiar enough with the older AMD’s and your unique system. However, you may want to check in the BIOS to make sure there isn’t a setting somewhere that is limiting the speed of the processor. It would be wise to also find out what motherboard you are running, and what BIOS, so you can look up specific information about the settings that can alter CPU performance. ---
**Author:** ![simple\_homer](https://avatars.discourse-cdn.com/v4/letter/s/9de0a6/32.png) [@simple\_homer](https://boards.straightdope.com/u/simple_homer)\ **Post date:** [June 21, 2005, 6:48pm UTC](https://boards.straightdope.com/t/replacing-an-amd-athlon-processor/309232/3 "2005-06-21T18:48:29Z")
Hi Fringe, that was a fast reply 🙂 I do not know enough about the BIOS, I looked already, and I can’t see anything that I know to change. I did post the info about the motherboard, and these are the specs for it: [http://www.powerspec.com/systems/archives/system\_components.phtml?component=328&selection=7805](http://www.powerspec.com/systems/archives/system_components.phtml?component=328&selection=7805) Hoping someone more computer literate than me can tell me what i need to do with the BIOS, if anything ---
**Author:** ![Nanoda](https://avatars.discourse-cdn.com/v4/letter/n/ce73a5/32.png) [@Nanoda](https://boards.straightdope.com/u/Nanoda)\ **Post date:** [June 21, 2005, 6:54pm UTC](https://boards.straightdope.com/t/replacing-an-amd-athlon-processor/309232/4 "2005-06-21T18:54:12Z")
There’s either a jumper on the board that needs to be set, or as **Fringe** says, a BIOS setting to change. You need the actual manual for your motherboard to check exactly what though, so go [here](http://tw.giga-byte.com/MotherBoard/Products/Products_GA-7ZMM.htm) and… click on ‘Manual’? I’m not sure, no time now. Somewhere there it should say what the exact settings for a 900Mhz Intel chip are, and you can get your system running properly. ---
**Author:** ![RandomLetters](https://avatars.discourse-cdn.com/v4/letter/r/8edcca/32.png) [@RandomLetters](https://boards.straightdope.com/u/RandomLetters)\ **Post date:** [June 21, 2005, 7:04pm UTC](https://boards.straightdope.com/t/replacing-an-amd-athlon-processor/309232/5 "2005-06-21T19:04:28Z")
You are going to have to go into the BIOS, and change the Front Side Bus (FSB) speed, and the CPU clock multiplier. Right now, it is probably set at 100 mhz x 5 or 133 mhz x 4; try setting these to 100 mhz x 9 or 133 mhz x 6.75. Hopefully that works. ---
**Author:** ![Fringe](https://avatars.discourse-cdn.com/v4/letter/f/b5a626/32.png) [@Fringe](https://boards.straightdope.com/u/Fringe)\ **Post date:** [June 21, 2005, 7:08pm UTC](https://boards.straightdope.com/t/replacing-an-amd-athlon-processor/309232/6 "2005-06-21T19:08:48Z")
> [@RandomLetters](#): > > You are going to have to go into the BIOS, and change the Front Side Bus (FSB) speed, and the CPU clock multiplier. Right now, it is probably set at 100 mhz x 5 or 133 mhz x 4; try setting these to 100 mhz x 9 or 133 mhz x 6.75. Hopefully that works. That’s probably your best bet. And as **Nanoda** said, an actual manual could be very helpful. Sorry about overlooking the motherboard information you posted, I’m only half awake right now as I’m still at work. ---
**Author:** ![RandomLetters](https://avatars.discourse-cdn.com/v4/letter/r/8edcca/32.png) [@RandomLetters](https://boards.straightdope.com/u/RandomLetters)\ **Post date:** [June 21, 2005, 7:19pm UTC](https://boards.straightdope.com/t/replacing-an-amd-athlon-processor/309232/7 "2005-06-21T19:19:21Z")
Well, looking at the manual provided, it seems this won’t be as easy as messing around in the bios. You will have to mess around with the jumpers. Page 14 of the .pdf has the diagram for setting the system bus speed - set the jumpers for the 133mhz setting. ---
**Author:** ![simple\_homer](https://avatars.discourse-cdn.com/v4/letter/s/9de0a6/32.png) [@simple\_homer](https://boards.straightdope.com/u/simple_homer)\ **Post date:** [June 22, 2005, 5:44am UTC](https://boards.straightdope.com/t/replacing-an-amd-athlon-processor/309232/8 "2005-06-22T05:44:08Z")
Thanks for all the replies so far. I was able to set the FSB to 115 MHZ, using the jumpers, but the computer will not boot at 133MHZ. How do I set the multiplier? I do not see any info about that anywhere. XP says the processor is not running at 579MHZ, with the FSB at 115 MHZ. I have no idea what the multiplier is set at now, or where i can adjust it. ---
**Author:** ![simple\_homer](https://avatars.discourse-cdn.com/v4/letter/s/9de0a6/32.png) [@simple\_homer](https://boards.straightdope.com/u/simple_homer)\ **Post date:** [June 22, 2005, 5:45am UTC](https://boards.straightdope.com/t/replacing-an-amd-athlon-processor/309232/9 "2005-06-22T05:45:53Z")
should read as “XP says the processor is NOW running at 579MHZ, with the FSB at 115 MHZ.” ---
**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\ **Post date:** [June 22, 2005, 10:46am UTC](https://boards.straightdope.com/t/replacing-an-amd-athlon-processor/309232/10 "2005-06-22T10:46:40Z")
". How do I set the multiplier? " Those AMD chips are clock locked, so setting the multiplier has no effect. There are some work arounds. The chip has some (wires?jumpers?) on the top, it just looks like short lines, some are cut. Some of these have been cut by a laser, which sets it’s multiplier. You should be able to find which ones have to be restored (or perhaps cut) to change the multiplier. To restore a line I heard the suggesting to use a #2 pensil and heavially draw it back in (the graphite is conductive enough to work). Good luck. ---
**Author:** ![Shalmanese](https://avatars.discourse-cdn.com/v4/letter/s/45deac/32.png) [@Shalmanese](https://boards.straightdope.com/u/Shalmanese)\ **Post date:** [June 22, 2005, 12:43pm UTC](https://boards.straightdope.com/t/replacing-an-amd-athlon-processor/309232/11 "2005-06-22T12:43:10Z")
The 900Mhz processor runs on a 100Mhz bus so setting it to 133Mhz would just damage it. Most likely, either the multiplier is unlocked and the board defaults to the lowest or you actually have a 500Mhz processor. Keep the bus at 100Mhz and set the multiplier to 9x if you can. Also, try finding the core stepping on the CPU and plugging it into google to see what actual processor you have. post it here as well so we can help better. ---
**Author:** ![Jurph](https://avatars.discourse-cdn.com/v4/letter/j/50afbb/32.png) [@Jurph](https://boards.straightdope.com/u/Jurph)\ **Post date:** [June 22, 2005, 4:59pm UTC](https://boards.straightdope.com/t/replacing-an-amd-athlon-processor/309232/12 "2005-06-22T16:59:51Z")
If you can unsocket the CPU and compare it to [this chart](http://www.idhw.com/textual/guide/noin_cpu_amd.html) then you can tell for sure that you’ve got the CPU you think you do. Once you know the name, check out [this page](http://www.idhw.com/textual/guide/noin_cpu_amd_k7core.html) where you can identify which clock speed the chip is truly meant to run at. My wife has a Gigabyte GA-7VM (not the 7VMM, unfortunately!) which is similar to yours and I have had problems getting it to run at the stated “stock” speed of the chip. I’ll look inside the case and check the BIOS settings – I remember having to do something that I considered “voodoo” to get it working, but I don’t remember what it was. I also remember that the table of jumper settings in one of my motherboard manuals was wrong, and that the DIP switch arrangement in the manual did not actually correspond to the FSB speed I was trying to achieve – if it was the Gigabyte manual, I may be able to give you a better idea of what jumper settings to try. Also, out of curiosity: are you running PC-100 or PC-133 RAM? ---
**Author:** ![simple\_homer](https://avatars.discourse-cdn.com/v4/letter/s/9de0a6/32.png) [@simple\_homer](https://boards.straightdope.com/u/simple_homer)\ **Post date:** [June 22, 2005, 6:46pm UTC](https://boards.straightdope.com/t/replacing-an-amd-athlon-processor/309232/13 "2005-06-22T18:46:11Z")
Ok, the processor is an AHM0900AVS3B which, from the information I have seen online indicates that it is a mobile processor for a laptop ? And according to here, [http://myplc.com/sony/docs/amd\_processor\_reference.html](http://myplc.com/sony/docs/amd_processor_reference.html) the FSB should be 200MHZ ? So… since my motherboard has a maximum of 133MHZ, should I just leave the FSB at 100 MHZ, and let the processor function as a 500 MHZ, or is there something I can do to speed things up ? Overclocking I guess ? How would I go about using this processor in this motherboard at the highest speed possible. Again, I am in the Philippines, and I do not have any access to other compatible motherboards or processors. The memory is PC133, with a total of a 192MB (128+64) I am guessing it being a processor built for a laptop does not hurt anything being in my desktop , or does it ? Thanks to all !! ---
**Author:** ![simple\_homer](https://avatars.discourse-cdn.com/v4/letter/s/9de0a6/32.png) [@simple\_homer](https://boards.straightdope.com/u/simple_homer)\ **Post date:** [June 22, 2005, 6:48pm UTC](https://boards.straightdope.com/t/replacing-an-amd-athlon-processor/309232/14 "2005-06-22T18:48:13Z")
Oh, and the processor is a 900 MHZ processor according to that model number on the CPU ---
**Author:** ![Shalmanese](https://avatars.discourse-cdn.com/v4/letter/s/45deac/32.png) [@Shalmanese](https://boards.straightdope.com/u/Shalmanese)\ **Post date:** [June 22, 2005, 11:03pm UTC](https://boards.straightdope.com/t/replacing-an-amd-athlon-processor/309232/15 "2005-06-22T23:03:08Z")
I don’t know how you managed to get a mobile processor but you should set the FSB to 100Mhz. The processor internally doubles the FSB to get 200Mhz. You want to look for a multiplier dipswitch or bios setting and set it to 9. ---
**Author:** ![Shalmanese](https://avatars.discourse-cdn.com/v4/letter/s/45deac/32.png) [@Shalmanese](https://boards.straightdope.com/u/Shalmanese)\ **Post date:** [June 22, 2005, 11:04pm UTC](https://boards.straightdope.com/t/replacing-an-amd-athlon-processor/309232/16 "2005-06-22T23:04:10Z")
Oh, another thing it may be is that the chip is going into low power consumption mode since it’s a laptop chip and the desktop wasn’t built to handle it. ---
**Author:** ![Jurph](https://avatars.discourse-cdn.com/v4/letter/j/50afbb/32.png) [@Jurph](https://boards.straightdope.com/u/Jurph)\ **Post date:** [June 23, 2005, 2:16am UTC](https://boards.straightdope.com/t/replacing-an-amd-athlon-processor/309232/17 "2005-06-23T02:16:07Z")
> [@Shalmanese](#): > > I don’t know how you managed to get a mobile processor but you should set the FSB to 100Mhz. The processor internally doubles the FSB to get 200Mhz. You want to look for a multiplier dipswitch or bios setting and set it to 9. I (take note that I’m not the OP!) specifically bought a mobile processor for my machine because they use less power and generate less heat at full power; it’s not difficult or all that unusual. As for the 100MHz / 200MHz question, **Shalmanese** is right, I think: your motherboard doubles the FSB transparently up front. So the problem right now is that your motherboard is only seeing a x2.5 multiplier, but you are capable of running at a x4.5 multiplier. I’m not sure if there’s also a transparent division by two somewhere in there, though, so you may need to think of them as x5 and x9 anyway. You might try disconnecting unnecessary peripherals or adding a stronger power supply – it could be that the motherboard just can’t drive the CPU any faster at the current wattage. But since you’re using a mobile (and they use less power anyway) that’s probably not the problem. ---
**Author:** ![Jurph](https://avatars.discourse-cdn.com/v4/letter/j/50afbb/32.png) [@Jurph](https://boards.straightdope.com/u/Jurph)\ **Post date:** [June 23, 2005, 3:40pm UTC](https://boards.straightdope.com/t/replacing-an-amd-athlon-processor/309232/18 "2005-06-23T15:40:42Z")
Try [CrystalCPUID](http://crystalmark.info/download/index-e.html) and let us know what your machine thinks it’s running at. You may be able to alter the FSB and multiplier while the system is running, and get your machine up to a more reasonable speed. I think I was wrong above when I said the FSB is actually running at 200MHz – you would need to be running VIA’s KT-266 chipset for that to be the case. You may be limited to (5 x 133) = 667 MHz with this motherboard and CPU. If your RAM is only PC100 (instead of PC133) it may be holding back your ability to run your FSB quickly. If that’s the case, then you’ll have to do a cost/benefit analysis of whether a new motherboard (and new RAM, and probably a new PSU) is worth the speed increase, or if you want to look for the fastest AMD CPU out there with a 133 FSB.