AMD Athlon 64 3000+ 3400+ - 2.2 GHz Single-Core (ADA3400AEP5AP) Processor
Fast socket 754 CPU, but old/dated now.
(18/12/2009) Good upgrade CPU if your coming from a Sempron (or maybe a Athlon 64 2800). @ £30'ish MUCH better bang for buck than the rare and only 5% faster Athlon 64 3700. However, its probably better to consider a cheap AMD socket AM2 or Intel socket 775 dual core bundle ...Read full review
AMD Athlon 64 X2 4000+ 4000+ - 2.1 GHz Dual-Core (ADO4000DDBOX) Processor
Low end Athlon 64 X2's - a fantastic upgrade for single core users.
(reviewed March 2012) Excellent bang for buck. Should work in 99% of AM2 motherboards, fairly low power usage, runs cool, no need for expensive/large heatsink, able to play full screen HD smoothly (unlike single core Athlon 64's). However not much good for playing the latest...Read full review
AMD Athlon 64 X2 3800+ - 2 GHz Dual-Core (ADO3800IAA5CU) Processor
AMD dual core (socket AM2) for £20'ish!
For around £20 (18/12/2009) this is a great value dual core CPU. Why buy an expensive quad core CPU for basic computing tasks? Why buy a single core AM2 Athlon 3500/3700/4000 for a similar price? These slightly older CPU’s should work in 99.9% of AM2 motherboards too :)