Voir la version complète : AMD and Hyper Threading

03/02/2006, 19h49
I have an AMD 64 FX-55 cpu in my new computer. It states that it has Hyper Threading. Before I had a P4 with HT and windows reconized it as 2 processors including Carrara at rendering time.

Now the question is, why does an Intel cpu show as 2 processors with HT but not AMD?

04/02/2006, 10h38
AMD and HT? Are you sure about that?

04/02/2006, 14h13
I think what you saw was hypertransport which is AMD's marketing term for their fast bus to memory I believe. AMD does not have hyperthreading.


Pete Exxtreme
04/02/2006, 14h29
I would think that this processor has 2 cores rather than Hyperthreading, with is far better as it's a REAL dual processor. If carrara don't see them, i would check i the HT option is activated, if so maybe that your PC BIOS is not (yet) configured to use the dual core ???

Something also i wonder is if you're using XP home rather than XP Pro, if it can see dual-proc ? XP home can see HT... but not sure for 2 cores ???
Just my 2 cents...

04/02/2006, 18h37
AMD has Hyper Transport Protocol, not HyperThreading. The latter is exclusive to the Pentium 4 and Intel. Intel's HyperThreading splits a single core processor into 2 Virtual Processors.

04/02/2006, 20h01

WinXP Home does take advantage of the dual cores, and the 1 and 2 labeled squares indeed show up when Carrara renders. (I've got the Pentium D 840.)


Pete Exxtreme
04/02/2006, 20h47
Thanks for the info Chris :hi:

14/02/2006, 09h49
You are right, AMD has Hypertransport not hyperthreading. The FX-55 is a single core processor and therefore will show up as one processor. If you want dual processing, you need one of AMD's Dual processors.

Note - a hyperthreaded P4 will still only perform equivelent to a similar specd AMD processor, as it dosen't have the cache and pipelines to act as true 2 processors, even their new P4 dual core dosen't improve as much as it could as it has a shared cachE memory for the two processors- and runs very hot too !

If you want the equivelent of your FX55, its the new FX60 which is dual core, but extremely expensive (but easily outperforms the new P4 dual core extreme version - by 10-20% in some tests).

The other option is to go for a standard dual processor such as the AMD 4800+ which has very good reviews and will probably halve your render time over even the the FX55 and costs around £450 in the UK. Ensure you get the 1Mb+1Mb cache version as this will be better for memory intensive work like rendering (there is a cheaper 512Kb + 512Kb version available)

See this comment below for comments on 3D modelling:

Arguably, what works for one architecture may not necessarily be the all encompassing solution for the other architecture. Suffice it to say that as a rule of thumb multiple threads, running simultaneously as in the case of multimedia (http://www.lostcircuits.com/cpu/amd_x2/#) encoding, will experience more improvements than applications that are targeting single threads or even use the same resources for all threads running. Cases in point are 3D rendering programs such as Caligari TrueSpace or 3dsmax that may show logical processors in the form of independent scanlines, whereas the overall runtime is completely oblivious to the number of such units. The benchmark results will always be the same. No rules without exceptions, and the best known or publicized benchmark showing results to the contrary is Maxon's Cinebench 2003. In that case, HyperThreading makes a huge difference, at least for the raytracing

This is from :