Gigaflops......true measure of speed?

[The Edge]

A friend of mine were having a debate on which is better....Mac vs. PC when it comes to raw encoding power.
Now, I don't really care which is, and I'm not planning on starting a debate either. I will say though, I believe the G4 processors are better.
Anyway, he was basing his debate on Gflops as apposed to Mhz.

I work at the moment so nothing better to do but to look this up:)
The Mac basiclly is king here.
The original single processor 500MHz Power Mac G4 had a measured peak performance of 3.7 gigaflops. The new dual Power Mac G4 is running at 18.3Gflops. Wow you say.

When compared to other cpu's.
Power Mac G4 = 18.3 Gflops
P4 2Gz = 1.4 Gflops
Athlon T-Bird 1.5 = 1.9 Gflops

I know there is alot more to a CPU's performance then Gflops

I was looking up some info on processors as I plan on upgrading soon and this got me thinking. At the moment I have an Athlon 1.4, which I found runs at around 1.8Gflops (gigaflop is a billion floating-point operations per second)
On average, my system encodes at around 20-27fps (standard GKnot setup) which in turn is around 4 hours approx for most encodes. Good enough for me.

Now, the NEC's Earth Simulator, that fastest computer in the world at the moment, runs at 40 teraflops (Forty trillion operations a second)
Doing the maths, in the 4hours it takes my system to encode, that's 1,440,000,000,000 floating-point operations in total (approx:))
That would take the Earth Simulator 3.6seconds to encode both passes!! Ouch.
Hope the sums are correct. Yes, I did carry the one!!!

I also came across that if the human brain could be run like a CPU, is something like 10 quadrillion instructions per second. Again, doing the maths:eek: , it would take 0.144, or 15th of a second.

All this just gives you an idea of what is under the bonnet (hood for those Americans) at home in your PC. It could have been a "Super-computer" 5 years ago. Remember the days of the Atari 800XL or even the SinclairZX Spectrum.
Ah yes. Also, that it won't belong before processors match and surpass the human brain, the best cpu there is. I read that by 2010, the "Pentaflop" barrier will be broken. Ouch!

Well, I'll have to get back to work now.

I did see a Cray Supercomputer on E-bay for $44,500. It was $10 million when it debuted in 1991!!!! Cray Research Y-MP C90 @ 16Gflops /sec.
I might as well ask. Who has the fastest rig here in Doom9???

[TactX]

Judging a CPUs performance just by FLOPS is very vague. It is a highly theoretical value. The real-life performance depends too much on other factors like pipeline length, cache-hits/misses, size and speed of L1/L2-cache, special SIMD instruction-sets........

If you really want to know which CPU/system is faster for a certain job (encoding in this case), you have to make your own tests under the (almost) same condiditons for both.

Also do not forget the integer performance. Most operations are still integer imho (depending on the job of course).


Greets

[Koepi]

Interesting point, Edge :)

But - there is a but.

Floating point doesn't get used much in encoding.
The codecs are optimized - for MMX, SSE, AltiVec.

That has a reason: with those kinds of commands you can process a bunch of pixels at the _same_ time (floating point would need at least 1 instruction/pixel, where with MMX you can have 8 pixels manipulated with instruction).
The codecs also try to get rid of as much floating point as possible.

Then we have the memory bandwidth - limiting that again.

So, I'd say - playing quake1 is at least much nicer on a G4 as on x86 architecture as the rendering engine is using floating point excessively.

Not quite video encoding, but video gaming ;)

Just wanted to add these thoughts.

Best regards
Koepi

[MfA]

Your mac friend lives in a distorted reality, but then that (http://www.apple.com/switch/ads/ellenfeiss.html) is what being a mac user is all about ;)

18.3 GLOPS for a dual G4 is peak performance, those x86 numbers are not.

[The Edge]

Yeap, that's what I was trying to explain to my "distorted" friend!
You can't base cpu performance solely on Gflops.
Anyway, I was really just pointing out the way processors are advancing and just how fast they are.
I think I print this info out and make him "eat" his own words ;)
Thanks for your thoughts. Back to work now. I'm have to save for my Cray Research Y-MP C90:D

Edge

[Arky]

Originally posted by The Edge

Now, the NEC's Earth Simulator, that fastest computer in the world at the moment, runs at 40 teraflops (Forty trillion operations a second)
Doing the maths, in the 4hours it takes my system to encode, that's 1,440,000,000,000 floating-point operations in total (approx:))
That would take the Earth Simulator 3.6seconds to encode both passes!! Ouch.

Not the fastest for much longer! :D :D :D

http://www.ibm.com/news/us/2002/11/19.html

#I WANT ONE!!!# :devil:

I reckon that'd let Cinemacraft encode a full three hour DVD in, erm... about a HALF a second!! (nope, I didn't actually do the maths...). I'd like to see the RAID setup that could handle the bandwidth required for such an encoding job, too! :D


Arky ;o)

[[Toff]]

This one is less powerfull (665GFlops) : http://space-simulator.lanl.gov/
but you can build it at home ;)
Just some little shuttle. :D

[Arky]

Originally posted by [Toff]
This one is less powerfull (665GFlops) : http://space-simulator.lanl.gov/
but you can build it at home ;)
Just some little shuttle. :D

665GFlops? PAH!! hardly worth even BOTHERING with!! :D :D :D

Not fast enough for me, I want MORE POWER!

I look forward to the day wehn IBM do a thinkpad with this kind of power, for under $2,000

How long do you reckon I'll have to wait? 12 years?


Arky ;o)

[The Edge]

Earth Simulator's (http://www.es.jamstec.go.jp/esc/eng/) home page.

Check out this site too.
http://www.top500.org

[diji1]

Looking forward to encoding mpeg4 on my watch computer ;).

In pure layman's terms ( that'd be me ): the GigaFlop model doesn't have much relevance to any real world performance and can safely be ignored. lol, macs faster than pc ... perhaps Mhz does matter after all!