One of the latest trends in CPU / processor technology is “dual core” or “multi core” processors. Processors previously designed all sit on one chip, with one core. The core does all the logic and thinking while the “chip” connects the core to the rest of the system and handles the requests, houses the cache (onboard memory), and other logic activities. Dual Core means there is litterally 2 cores sitting on a single chip. Intel was the first to accomplish this feat with the release of the Pentium D series. The Pentium D was labeled by the tech community to be a very inelegant way of implementing dual core as it essentially was 2 Pentium 4 cores slapped together on a single to form Pentium D. This meant that very little was done to optimize the process. AMD soon followed up with its Athlon X2 series which was regarded as a much more elegant and true to purpose Dual Core design.

Dual Core CPU’s usually run slightly lower clockspeeds (per core) then the higher end single core processors. This is generally to help cut costs as well as maintain a safe thermal envelope. Having 2 cores in such close proximity creates significantly more heat and as such, the first dual core processors had significantly lower clockspeeds (per core).

RAM: Vendors randomly decide to list their ram speeds based on a “PCXXXX” standard or a MHz standard, they convert based on a formula related to data transfer rates. PC2100 = 266 MHz, PC3200 = 400 MHz, PC4200 = 533 MHz, PC5300 = 667 MHz, PC6400 = 800 MHz. There is of course more divisions inbetween, before, and after but these are the big ones. Something that needs to be considered though is there is also DDR(1) and DDR2. The original DDR has “latency” (time for data to get from one point to another) significantly lower then DDR2. This is sort of like how cache differences work. DDR2 was designed with higher latencies (bad) but higher bandwidth as well (good). DDR(1) generally ends at PC3200 (highest official bandwidth of DDR) and DDR2 generally starts at PC4200. The PC4200 / 533 MHz, again, refers to bandwidth. This is how many megabytes (MB) per second are possible to transfer across the memory bus. Again though, DDR2 has significantly higher latencies so it takes longer for that larger amount of data to get where it’s going. The industry can’t seem to decide on a standard but over the last few years it has migrated to DDR2 due to lower costs. DDR2 also uses less energy as compared to DDR due to higher efficiencies, a smaller manufacturing process and less power intensive design. Very extreme performance nuts still tend to prefer DDR(1) due to its significantly lower latencies.

This is a simplified quality explanation of CPU cache and how it works. Many folks wonder why some processors have very little cache and others have enormous amounts as well as how it works.

Cache: The Athlon X2 has 2x 512KB cache allocations for L2 Cache. This is a very small data block (memory) built directly into the CPU itself. This is very high speed memory (exponentially faster then RAM) used for storing each block of data to be processed by the CPU as it enters. There are several “levels” of cache which are related to how they connect to the CPU (hence L1, L2, etc). L2 Cache is almost always the quoted part of any processor detail. Cache is also faster/slower and bigger/smaller. Think of it like a road. A 2 lane road with a 35mph limit should move just as many cars as 1 lane road with a 70mph limit (obviously this makes traffic patterns simplified but, its an example). In this case, the Athlon X2′s cache is very fast (think 70mph limit) but cannot contain a lot of data at a time (1 lane). AMD actually has 2x 1MB L2 cache processors in their FX and Opteron lines. The difference in performance with double the cache for AMD’s line of processors was about 1% in almost every application yet increased costs significantly. From a totally different perspective, Intel’s older line of Pentium 4, Pentium D series processors had huge amounts of L2 cache (up to 4MB!), Intel did this in an attempt to make up for a failing architecture, a band-aid fix to increase performance, though marginally. AMD’s Athlon X2 line uses separate L2 cache for each processor core (dual-core) so it really has a full 1MB on board (2x 512KB). Intel’s new Core 2 Duo line starts at 2MB and goes up to 4MB with their higher end Core 2 Duo’s. More cache generally means better performance, but when dealing with cache – there is extreme diminishing returns, cost goes up incredibly quick and performance increases are minimal. When I say “performance” in relation to CPU cache – it generally translate to the end user as slightly faster access times when doing things like starting a program or opening a file as the first bits of data to crunch are quickly grabbed from the file system. In reality, the difference is going to be incredibly minimal as long as the CPU is not “data starved”. This is what happens with the very low end CPU’s from Intel (Celeron) and AMD (Sempron). They have very small L2 cache blocks and the CPU crunches the data faster then the L2 cache can call and store it, the CPU ends up idling; waiting on data. If you do want to go with a CPU with more cache, we can look at upgrading the CPU to a higher rated Athlon X2 with 2x 1MB L2 (I believe the 4400+ has 2x 1MB) or to a FX series AMD CPU. All in all, 2x 512KB is indeed not a smaller then average cache size. The first Intel Celeron chips had zero L2 cache.