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On Sat, 18 Oct 1997 15:12:13 -0700 (PDT), Steve Parker wrote: >On Sat, 18 Oct 1997, Paul Khoury wrote: > >> Actually, believe it or not, the DX4-75 is based on a >> 25MHz clock, and the 100 a 33MHz clock. Go figure, >> since 3*33=99, close to 100. > > Yes, Intels IntelDX4 aka '486DX4 runs clock tripled. We know that. >What PEP is doing is putting an AMD '5x86-133 CPU [which runs clock >tripled or quadrupled] onto a 25MHz bus and getting 100MHz out of it. It >is obvious that they are running in 4x25MHz mode. If it were easy to get >a 33MHz bus rate out of a TP701 I'm sure IBM would have done it if only to >help with the very lackluster CPU performance of an otherwise very nice >product. > >> That rating should only be relative, since it seems a lot of 701 users have >> also used Linux, and OS/2, which use the processor more efficiently, the same >> for resources. > > The effect of the L1 cache [or any cache for that matter] size is very >much up to the code being run. For big things that overwhelm the cache, >cache size doesn't seem to matter much at all. On one P133 system I built >Quake was less than 2% faster after upgrading L2 cache from 256K to 512K. >Quake uses huge sets of data and overwhelms the pitiful 512K L2 cache. I >suppose a few MB worth of L2 cache might have helped. For small stuff >like DOS apps 512K L2 cache can almost completely cache the first 640K and >the code nearly always runs from L2 cache. This would give you a >fantastic speed increase. > >> I thought that the DX4 had a 16K cache, >> with write back also. > > It has 16K L1 cache with optional write back. I believe the magazine >folks just didn't pay attention to which CPU was in which machine. Nearly >everything I read said the 75MHz TP701 had the DX4 CPU in it. The >difference between 8K L1 cache and 16K L1 cache is minimal for most >things. Especially with no L2 cache to back it up. > > And re: Winstone.. Winstone is known for being a pretty darn >inaccurate measure of system performance. Winbench can tell you a good >deal and is about as a reliable "typical windows application" benchmark as >you can get. I personally tend to use Quake and other goodies like ctcm >and threadmark to make measurements more in tune with what I do. After >all, how a system performs running the apps you use is what mattters. =) > But what ever happened to Dhrystones and Whetstones? That's what I typically used. That'd actually be an interesting internet project - Generistone - benchmarks for Windows 3.x, 95, NT, OS/2, Linux and DOS (sort of like projects that take say an emulator or a web server like Apache and port it to other OSes). Just my 2 cents. Paul