New CPU: Which is better - faster clock or more cores?

[jeremiahmoore]

Frankly, I suspect there's no ready answer to this question... But here goes anyway.

I'm in the market for a new CPU. I believe there's usually a sweet spot in the market, where you get the most computer for the money. But now there's another wrinkle in the equation with the current models available: more slower cores vs. fewer faster cores.

For instance:

4-Core: One 2.8GHz Quad-Core Intel Xeon "Nehalem" at $2488 (3GB ram)

-vs-

8-Core: Two 2.26GHz Quad-Core Intel Xeon "Nehalem" at $2599 (with 6GB ram, making up for the difference in price more or less)

My hunch for the near term is that PT will perform better with a faster clock speed vs more cores, even though there is technically less processor available.

Why? Because I believe PT is not efficient at using all the cores. Yet. But will it be?

Anybody have any info, opinion, conjecture to share here?

-jeremiah

[mikevarela]

Digitech support should chime in here...

I believe however that PT has been written to take advantage of multi-core systems and as such it would be prudent to go for the larger number of cores vs. speed. Many things happen inside a computer, PT is just one of them. A tuned system will allocate processes in parallel if the processing is there. All CPU processing is serial based, but hyper threading and multi core systems side step the serial address by giving more options for internal calculation routing. An idle system still processes input and handles events, so in a multi core system the computer can delegate certain processed to some cores and use others for system material.

Speed is nice, but parallel is always better.

Another thing comes into question as well. Mac keeps changing the processor, so often you'll notice a lower clock level on the newer models, vs a larger on the previous generation. The westmere's just surfaced in the 12 core (and 8 i think), yet you can find higher speeds in the 8 nehalem top end.

If it was up to me and a question of the cost difference you proposed, I'd go for the 8 core and lot's of ram. All things being equal, go higher clock speeds if you can handle the cash jump, but the opposite if you gain horsepower by increasing the number of chips

[tom_lowe]

Pro Tools will take advantage of multiple cores for RTAS processing, but the application itself isn't yet multithreaded - hardly any are. Apple's introduction of Grand Central will help developers use multiple cores, but very few apps currently do this.

Digi Tech support might like to chime in, but in benchmarks for the last generation of Mac Pro, the quad-core with higher clock speed out performed the 8 core at a lower speed.

Of course when all applications are truly multi-threaded, the more cores your system has will be of more use than higher clock speed, but we're not there just yet.

[Postman]

I'm with Tom,

Pro Tools seems to do many tasks that are confined to realtime. It is usually disappointing to upgrade to a computer that blows away your old one, yet Pro Tools barely notices. I'd go for faster 4 cores, maybe bump up the ram a bit. You'll be ungrading again before Pro Tools is taking advantage of hyperthreading, IMHO.

[jeremiahmoore]

Tom and Postman - this is my hunch, and my understanding as well: that PT is not (very?) multithreaded (yet) and it'll likely be a while, given that's it's a complex real-time app with roots in a very old codebase.

I'll ask around to folks I know at Digi / Avid and see if anything emerges from that. If I learn anything of value, I'll post it back here!

Tom - what benchmarks are you referring to - pro tools-specific ones?

-jeremiah

[D'Animation]

8-cores is great but as mentioned below, it does seem like 4xfaster cores outperforms that standard 8-core config. Check out macworld.com - they do pretty good benchmarks comparing old models along with variations of the new products - not protools tests but you'll get the gist of their findings...

[browniespeaks]

i5 560m w/4GBRam (out of the box w/ only half the mandatory optimizations) Is a noticable improvement over Athlon X2 4800+ w/8GB ram (well tuned machine). MIPS is not apples to apples on this comparison but I didnt think there would be too big a difference for basic editing. I was wrong. Both running windows 7 pro

[tom_lowe]

No one does benchmarks on new Macs for Pro Tools, if they did, I'd have said, think they were done by barefeats.

Point is, if a 4-core machine is faster on apps that aren't multithreaded, then that would apply to Pro Tools.

The only advantage of multicore on Pro Tools is RTAS processing.

Avid really should start over with the Pro Tools code, making it 64-bit and multithreaded, the only problem is that by doing so, they would make TDM totally irrelevant, so in this case, it's not actually beneficial to them to improve their code.

[tigas]

The big limitation with the Mac 4-cores is that your memory expansion is limited. However, since ProTools is still 32-bit and can't possibly address more than 4GB of memory, 6GB is the upper limit of what's useful, so you might as well spec the MacPro with that amount (3x2GB) from the factory, kick back and relax.

[Postman]

Huge amounts of memory may be meaningless to Pro Tools anyway, in my experience (post without VIs). For instance last year, on a PPC with PT8.01, I had a session with 17000 audio files and even more regions and edits. I was having problems with stability while Audiosuiting, editing was sluggish and while conforming I was having freeze ups from time to time. I increased ram from 2.5gb to 6gb. There was absolutely no improvement. I ended up lowering the number of undo's from 32 to 16, then to 8, eventually to 4. Only then did the freeze ups stop. The other problems did not improve until I was done with that project. As I said, extra ram did not seem to make any difference.