One month ago we reviewed the Intel E8400 here. We could not determine if the smaller brother E8200 will be that good, as well, so we took a chance to test a boxed E8200. This CPU is, of course, slower at nominal speeds, but we will concentrate on overclocking only.
At nominal speeds the CPU runs at 2.67GHz with an 8x multiplier. Otherwise, it's identical to the E8400 with 6MB 2nd level cache, 2x 32kB 1st level cache, FSB is also running at 333MHz.
We predicted that even an E8200 could reach 4GHz, and it did. But, it does take about 1.60V VCore; due to its 8x multiplier your board needs to reach 500MHz FSB; your memory has to at least be able to run at 1000MHz, as better results need better memory. We could not manage a better overclock due to the already very high VCore @ 1.60V.
The best compromise is a 3.60GHz overclock; it does not take that much voltage and runs with 450MHz FSB. The problem with the E8000 series is availability. While E8400 are almost nowhere in stock - backorders in Europe are in the range of three to five weeks, the E8200 can be an alternative, especially when you plan to buy a new system.
3.60GHz is quite a nice achievement, a 1GHz overclock. Reaching 4GHz is more difficult; you need a very high VCore of 1.60V, and it also does take a board which can reach 500MHz FSB. Some boards, especially the low-priced ones, can't do that always. Your memory needs to run at least with 1GHz. Our Biostar board, reviewed here, was able to do it, but it needed more voltage on the Northbridge and FSB to run the board in stable mode.
An E8400 is only €20,- more expensive compared to an E8200, but memory reaching 1.2GHz costs €50,-more or double the price of a standard 800MHz DDR2 CL4 2GB memory kit. For overclockers, the E8400 is the much better CPU,;consider the E8200 if you need a new system now.
You can check the CPU prices here.