In memtest86, the RAM is almost as fast as the L2 cache in Megabytes/second. The cache is 1.5X faster, but I think it should be much faster than this. I have an Athlon 64 X2 3800+ processor and 2GB Corsair Valueselect PC3200. On my laptop computer the L2 cache is 10X faster than the RAM!

memtest86 shouldn't be used as a memory/cache benchmark. It was written to scan for memory errors, not to measure memory/cache speed. For a more accurate benchmark, use SiSoft's Sandra. What kind of memory does the lappy use? Processor? Super P3-Now with Blu-Ray playback! PIII-S @ 1.66GHz 2GB PC2700 AGP HD3650 LiteOn BD-ROM Homebuilt 1080p projector w/ Pixelworks HDMI controller JBL 5.1 audio

Well Sandra is reporting better results, but I still think the cache is much too slow! Sorry, the laptop uses 1.5GB PC25300 and a Core Duo T2500 CPU.

You're comparing apples and oranges. AMD's cache and memory system is very different from Intel's. Intel CPUs rely on a large, screamin' fast L2 cache in order to perform. AMD CPUs, on the other hand, rely on screamin' fast memory access in order to perform. A high performance L2 cache just isn't (as) necessary for the Athlon 64. So while the Core Duo in your laptop has a much faster L2 cache, its main memory access isn't as efficient. Starting with the Coppermine Pentium III, Intel has been integrating very wide 256-bit cache buses to their processors. The fast cache compensates for the relatively poor memory performance of an external northbridge. AMD didn't focus nearly as much as Intel did on L2 cache implementation. The Athlon (XP) had a far-from-elegant 64-bit cache system. The Athlon 64 (X2) uses a much-improved 128-bit cache bus. Instead, AMD focused on giving their CPUs very large L1 caches (128KB total) as well as quick memory access. The K7 was the first CPU to dump the single data rate processor bus for a double-pumped design, and the K8 was the first CPU to forego the FSB and use an integrated northbridge. Thanks to this on-chip memory controller/northbridge, a K8 system's memory can be considered to be a very large L3 cache. It really isn't much of a surprise, then, that the L2 isn't that much faster than the very efficient, 128-bit memory access. So there ya go...and I just know that you're thinking to yourself, oh boy, I bet this guy loves to hear himself ramble :P Super P3-Now with Blu-Ray playback! PIII-S @ 1.66GHz 2GB PC2700 AGP HD3650 LiteOn BD-ROM Homebuilt 1080p projector w/ Pixelworks HDMI controller JBL 5.1 audio

thx, makes sense.