OK, we've got a server running an old Pentium III 550MHz with 256MB of memory. It does have lots of disk though (2x120GB, 18MB system and 60GB backup with Promise Raid and removable drives). This is the only machine long term that won't become a Shuttle box at some point because we need the drives. So, its a great toy and a good way to play with overclocking. I'm going to try to upgrade this for $400 or less and see what I can buy. Here's the analysis of what to get: | Component | Price | Comment | | AMD Athlon 2500+ | "$90":http://www.pricegrabber.com/search_getprod.php/masterid=688940/blsrt=1/ut=0ce4169308a239fb | 11x200MHz is a 3200+ Retail CPU has 3-year warranty, OEM has 30 days |
| ThermalTake "Silent Boost":http://www.tweaktown.com/document.php?dType=article&dId=519&81130 | "$26":http://www.pricegrabber.com/search_getprod.php/masterid=1365093/ut=0ce4169308a239fb | Seems strange to pay this much for a fan, but needed for overclocking | | ASUS A7N8X-X | "$69":http://www.pricegrabber.com/search_getprod.php/masterid=964340/ut=0ce4169308a239fb | A7N8X-Deluxe 2.0 if you need firewire |
| 2x Kingston KVR400X64C3512 | "$149":http://www.pricegrabber.com/search_getprod.php/masterid=894626/ut=0ce4169308a239fb | In January get for "$120":http://www.shop.kingston.com/0104kvr/default.asp?bannersource=extreme336 from Kingston directly |
| Total | $299 | Half of this is memory though | So I have$100 left in the budget, enough to buy another 160GB hard drive (WD16000JB at $115), a low end graphics card (ATI Radeo 9600SE at$50) or a new DVD Burner particular (Optorite DD0401 at $136) If we downgrade to 512MB of memory giving back$70 in the budget, then we can get to a larger hard drive (WD25000JB at $210) or a high end graphics card ATI Radeon 9600 Pro ($150).

h4. CPU
With Pentiums, the only way to overclock is to increase the bus speed of everything. But, the Athlon, with the right hardware and know how, you can leave the buses at their normal speeds and just increase the clock on the processor. here's how:
* "Athlon 2500+ becomes an Athlon 3000+":http://www.hardwareanalysis.com/content/topic/8507/. Not surprisingly lots of folks are asking if you can turn a 1.8GHz Athlon 2500+ that costs $87 into a 2.2GHz Athlon 3200+ that costs$300. The answer is that if you have an nForce2 chipset motherboard (like the ASUS A7N8X family) then you can do this. The BIOS lets you change the external clock frequency (on the 2500+, the default is 166Mhz x 11 CPU Multiplier to get you to 1.826GHz internally) by boosting the external clock frequency and raising CPU voltage (to 1.7v) while keeping the other buses for memory, PCI and AGP at their standards of 166Mhz, 33Mhz and 66MHz respectively (all of this is settable by BIOS). This works if you are lucky with your chip and also because I suspect that AMD sells these for cheaper to hit price points. You need a good cooler though since it will make the chip hot.
* "Viperlair":http://www.viperlair.com/articles/howto/cpu/unlock/. They have a great guide for Athlon XPs. They are at a good price right now. Main issue is that they are going to be obsolete as the Athlon 64 comes in. But, the pricing is not bad. Known motherboards that support this are the ASUS a7N8X, A7N8X-Deluxe, A7N8X-Deluxe 2.0, and A7N8X-X. The best way to see if it works is to download the manual from the manufacturer, they will go through BIOS settings for you.
* Coolers that people use include the Volcano 7 and 9 as well as the ThermalTake SilentBoost series.
* "PC Stats":http://pcworld.com/reviews/article/0,aid,112913,pg,1,00.asp. Reviewed the 2500+. Without increasing the CPU voltage or using a fancy fan, they got it to overclock to 170Mhz (from 133Mhz stock) and the muliplier went from 11 to 13x. Not bad results.
If you don't have a wonderful motherboard that does this.
* "XP-TMC Adaptor Socket":http://www.tomshardware.com/cpu/20030703/index.html. This is a piece of hardware that goes between the CPU and the motherboard socket and in effect decouples the processor clock from the bus clock. You can get this in bundles with motherboards for about $10-30 extra. A nice solution if you don't have a brand new motherboard that does this for you. All the new * Sharky Extreme. Or, you can go the manual route and connect together certain traces on the Athlon XP itself chip itself. "HighSpeed PC":http://www.highspeedpc.com/Merchant2/merchant.mv?Screen=PROD&Store_Code=HSPC&Product_Code=XPkit&Category_Code=OC makes a kit to do just that. * Other folks have used a car rear-window defogging "kit":http://www.nvnews.net/articles/athlon_xp_unlocking/page_2.shtml if you can believe that. * You can also use "Speed Strip":http://www.overclockercafe.com/Reviews/other_misc/Speed-Strip/ which is another hack that does the connection. h4. Motherboard You need a good motherboard for this. Most recently, the ASUS K7N8X-X shipped. It uses a cut down nForce2 chipset that doesn't have dual channel DDR memory. Turns out that this doesn't affect performance unless you are using a shared memory system, so its not big loss. The main loss from the K7N8X Deluxe 2.0 is there isn't firewire on this motherboard. But it costs saves$30 using this one ($110 vs.$70).
h4. Memory
You can spend quite a bit on memory. For instance, the Kingston HyperX series is about $220 for a 1GB set. It is a CAS2 latency, but their ValueRam series features CAS3 memory for$150, so there is quite a bit of price difference.
Corsair does the same thing, they have their TwinX line which are matched memory modules, XMS which are single performance and then they have a value line. The word is Corsair is higher performance, but Crucial is more stable as you overclock these things.
In the RAM world, overclocking by 10% is a big deal (e.g., going from 200MHz to 220Mhz). You should get pretty much identical performance from these brands if the ratings are the same as "Gruntville":http://www.gruntville.com/reviews/memory/kingston_hyperx4000/ showed with their test of DDR4000 memory comparing Crucial with Kingston HyperX. They got them both to 250MHz and were able to overclock them to 260MHz.