Originally posted by barkmonster
The Pentium 4!!!
Pentium 4 Denormalised Bug - This makes the CPU spike up to 100% usage whenever the level of audio drops below a certain threshold.
This very detailed article has tons of info about why the Pentium 4 isn't the wonder CPU Intel would have people believe. It details a few things that DEFINATELY make it 'not up to scratch' and 'missing features'
1. The Pentium 4 has no barrel shifter, it's a circuit which can shift or rotate any 32-bit number in one clock cycle. Every cpu from the 386 and 68030 onwards has had one of these.
2. The L1 cache is tiny, smaller even than the cache on a 486!
3. Only one machine language instruction can be decoded per clock cycle. Again, this is a pre 486 thing and not something an efficient CPU would do.
Actually, some of those aren't so bad.
1) bad
2) The reason why it's so small is so that it can be accessed in 2 cycles. No other L1 cache has been able to do that to my knowledge. The next P4 (Prescott) will have a 16k L1 cache instead of an 8k L1 cache.
3) This is because decoded instructions are stored in the L1 cache, removing the need to decode them again. It's one of the P4's major (only?) innovations.
4) There's another bad one. There's an instruction called FXCH that has been free (takes 0 cycles to execute) on previous x86 processors. It's very very useful to have it free, and the Pentium 4 doesn't.
Basically, the original Pentium 4 (Willamette) sucked big time. It was released prematurely due to the competetion from AMD. The current Northwood Bs are decent, and Prescott looks positively dangerous (800MHz bus, double L1 and L2 cache, even more optimized for high clock frequency, special threading instructions, etc...). The 970 is going to have a lot of work to do keeping up with Prescott, but I think it stands a chance. If the 970 and succesors can keep up until 2005/2006, the 32 bit Intel chips won't be able to address enough memory to keep up with them (assuming included memory doubles every year, high end computers will be shipping with upwards of 4-8GB by then).