M Harris wrote: > Although the analogy is going to be a little contrived, its something > like > the concept of cylinders in an internal combustion engine... there were cars > made back in the 30s-50s with 10, 12, and 16 cylinders... but due to > harmonics, balance, and other issues (8) seems to be the best (optimum) > number of cylinders. von Neumann processors are going to be similar... my > gut feeling is that 32 bit width is going to be optimum and that 64 bit is > the beginning of the end of no returns. I mean if PCs really ever do need to > have more than 4gig of real storage/virtual storage then.. .maybe. But also > remember that the processor's instruction set complexity (and performance) > play a role (are impacted).
Well, I guess in 2-3 years 4GB of RAM will be common. And it's definitely not only about bus, it's about register width (and therefore about ALU as well), which increased as well. 64bit registers help when computing numbers larger than "common" int. That was probably the idea behing ooooold 64bit MIPS, Alphas and such, whose real world speed may be compared with Pentium or even i486. 64bit CPUs are faster when working with large integers (which is not that frequent I presume), and they are a must when your application needs >3GB of memory. No other advantages here. I'm not sure where, but two or three years ago I saw a mysql and/or apache benchmark comparing 32bit vs. 64bit version performance on Athlon 64. If I remember correctly, 64 bit versions were faster by tens of percents. In other words, it depends on software as well. > I really think that multiple cores is going to be more practical (32 > bit) > than a wider bus. I would much rather have a quad processor (32 bit) right > now than a 64 bit bus... which for the most part I do not need. Well, talking about bus, 64 bit wide memory bus is here since SDR DRAM was introduced back in 1990's. Double channel efectively doubles that to 128bits I believe. Itanium 2 uses quad-channel memory bus and it gets quite confusing when considering multi-socket Opterons.... Multi-core - well, we get back to software then. Most people run single application and only small fraction runs more than 2 CPU intensive apps at a time. Realizing that most common today application software is single thread, you don't really need more than a double core. Quad core is investment for the future while the same goes for 64 bit CPUs. In fact, this discussion doesn't have a point. You can't buy 32bit only CPU (for common home use) anymore, at least there's no such worth mentioning. Yes, there's VIA, but it doesn't fit into "common home use". Cheers, Tosuja -- Petr "Tosuja" Klíma Mail: [EMAIL PROTECTED] Web: www.tosuja.info ICQ: 52057532 -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
