AMD64: The new performance king ?

[Admiral]

Nor really, I mean , the 2.4C has a nice price tag and all the chances of getting to 3.0-3.2 GHz with stock cooling. Dual channel is here (for all P4 models, depends only on motherboard) and so is Hyper Threading, as it is, with performance increase in some cases and decrease in a few (DivX encoding...). The 3.0 GHz Prescott is estimated to be 200-250$ at start, so it's a nice alternative for the extra cache and improved HT.

Now, I don't say that an Athlon64 3000+ (with a SIS 755 motherboard) doesn't look good, but they'll have to do the same thing for the socket 939 Athlon FX, get a 3000+ "castrated" version out for around 300$ or less.

[rugger]

However, stuff like divx encoding seems to be where the performance is needed. For the P4 to actually lose performance in one of the only tasks that actually take any signifcant time at all to do is very bad.

Edit: ok, the P4 is still faster then encoding then the athlon 64, so it seems I am digging myself a hole

Edit 2: although, the athlon does beat the snot out of the P4 in compiling programs, so linux users will love the A64

[Admiral]

Originally posted by rugger
However, stuff like divx encoding seems to be where the performance is needed. For the P4 to actually lose performance in one of the only tasks that actually take any signifcant time at all to do is very bad.

That's where the improved Hyper Threading on the Prescott is supposed to come in and fix the cache management "blunders" of the Northwoods.

[Indiana]

Originally posted by Admiral

Now, I don't say that an Athlon64 3000+ (with a SIS 755 motherboard) doesn't look good, but they'll have to do the same thing for the socket 939 Athlon FX, get a 3000+ "castrated" version out for around 300$ or less.

The Athlon64 FX is dead and so is Socket 939. Just look at the benches: The single-channel Athlon64 gets within 98% of the FX' performance when compared at the same clockspeed. Obviously, the A64 desing doesn't need/utilize the DualChannel bandwidth.
Even the MUCH cheaper Athlon64 3000+ with single channel and half the cache gets about 90-95% of the FX' performance when compared at the same frequency.

The magic with the A64 design seems to lie in the incorporation of the memory-controller into the CPU, not how wide it is. One major factor for the good performance seems to be the extremely low latencies that are achieved through this. Sometime latency is more important than max. throughput (comparable at HD when you just look at max. transfer and disregard seektimes...)


So there's no room for the A64FX: in the mainstream market the A64 does deliver the same speed at less than half the price - and for the Server-market there's the Opteron.
I would be strongly surprised, if AMD chose not to concentrate on two product lines in the future:

- 754 -> consumer (halfed Cache A64) and performance (A64) mainstream solution with single channel RAM.

- 940 -> server/workstation dual chanel(per cpu) registered memory with the Opteron and of course the multi-CPU capabilities.



P.S.: Your suggestion to get a castrated A64 3000+ with half the cache-size but dualchannel RAM out doesn't seem to be a good idea since the tests show that while halfing the Cache does have an (although minor) impact on the performance, the dualchannel RAM does nearly nothing.

P.P.S.: See e.g. here for a test of the A64 3400+ (single channel) against the equally clocked but dual channel A64FX51:

http://www.anandtech.com/cpu/showdoc.html?i=1941&p=1

[Indiana]

Originally posted by Admiral
That's where the improved Hyper Threading on the Prescott is supposed to come in and fix the cache management "blunders" of the Northwoods.

First tests showed the Prescott to be slower (or at best the same speed) at the same clock than the Northwood. Intel likely again have increased the pipeline length for the Prescott, thus reducing per MHz performance, but enabling insane clockspeeds.
The increased Cache makes up mostly for the longer pipe, but don't expect the Prescott to be faster interms of per MHz performance - it's potential lies in its clocking abilities...

And while DivX'ing might be slightly faster on intel now, it may not in the future. A 64 Bit version of DivX has been announced some time ago and is said to be released soon (now that MS has put out the free Beta of its Windows2003 64Bit for public testing).
Jérôme Rota, co-founder and leader of the codec team of DivXNetworks, talks about 18% higher performance when using the 64Bit version compared to the 32 Bit one.