No more mysteries: Apple's G5 versus x86, Mac OS X versus Linux
by Johan De Gelas on June 3, 2005 7:48 AM EST- Posted in
- Mac
The G5 as Server CPU
While it is the Xserve and not the PowerMac that is Apple's server platform, we could not resist the temptation to test the G5 based machine as a server too. Installed on the machine was the server version of Mac OS X Tiger. So in fact, we are giving the Apple platform a small advantage: the 2.5 GHz CPUs are a bit faster than the 2.3 GHz of the Xserve, and the RAM doesn't use ECC as in the Xserve.
| Dual G5 2,5 GHz PowerMac | Dual Xeon DP 3,6 GHz (HT on) | Dual Xeon DP 3,6 GHz (HT out) | Dual Opteron 2.4Ghz | |
| 1 | 192 | 286 | 287 | 290 |
| 2 | 274 | 450 | 457 | 438 |
| 5 | 113 | 497 | 559 | 543 |
| 10 | 62 | 517 | 583 | 629 |
| 20 | 50 | 545 | 561 | 670 |
| 35 | 50 | 486 | 573 | 650 |
| 50 | 47 | 495 | 570 | 669 |
Performance is at that point only 1/10th of the Opteron and Xeon. We have tested this on Panther (10.3) and on Tiger (10.4.1), triple-checked every possible error and the result remains the same: something is terribly wrong with the MySQL server performance.
SPEC CPU 2000 Int numbers compiled with GCC show that the G5 reaches about 75% of the integer performance of an equally clocked Opteron. So, the purely integer performance is not the issue. The Opteron should be quite faster, but not 10 times faster.
We checked with the activity monitor, and the CPUs were indeed working hard: up to 185% CPU load on the MySQL process. Notice that the MySQL process consists of no less than 60 threads.
| Concurrency | Dual Powermac G5 2.5 GHz (Panther) | Dual Powermac G5 2.7 GHz (Tiger) | Dual Xeon 3.6 GHz |
| 5 | 216.34 | 217.6 | 3776.44 |
| 20 | 216.24 | 217.68 | 3711.4 |
| 50 | 269.38 | 218.32 | 3624.63 |
| 100 | 249.51 | 217.69 | 3768.89 |
| 150 | 268.59 | 256.89 | 3600.1 |
The new OS, Tiger doesn't help: the 2.7 GHz (10.4.1) is as fast as the 2.5 GHz on Panther (10.3). More importantly, Apache shows exactly the same picture as MySQL: performance is 10 times more worse than on the Xeon (and Opteron) on Linux. Apple is very proud about the Mac OS X Unix roots, but it seems that the typical Unix/Linux software isn't too fond of Apple. Let us find out what happened!
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tfranzese - Friday, June 3, 2005 - link
Kind of snappy there Johan.I do prefer numbers coming from one source myself.
JohanAnandtech - Friday, June 3, 2005 - link
Rubikcube: Speculative? Firstly, Both a webserver and a database server show terrible performance. Secondly, LMbench shows there is definitely a problem with creating threads. So everything point into our "speculative" conclusion.Thirdly, as mentioned in an earlier post:
http://www-106.ibm.com/developerworks/linux/librar...
is another indication that there is nothing speculative about our conclusion.
rubikcube - Friday, June 3, 2005 - link
#21 I disagree. Most of the end of the article on the threading problems was speculative. We can't say that's the cause without actual testing.Jalf - Friday, June 3, 2005 - link
To those wanting a Linux on G5 test, keep in mind the entire purpose of this article. It was to test the performance of a Mac computer running a Mac OS, compared to a Intel/AMD PC.So while installing Linux on the G5 would give us a better idea of how the CPU itself performs, it would also leave out the huge effect the OS also has (You wouldn't have seen the huge performance problems with threading, for example.)
Jalf - Friday, June 3, 2005 - link
#11: Not true, if you browse AMD's documentation for a bit, they do say that their TDP *is* the absolute max power.Intel uses the "maximum power achievable under most circumstances"-method though.
rubikcube - Friday, June 3, 2005 - link
I agree that linux should have been used for a more normalized comparison. I also think that you should have tried running your mysql tests from darwin on x86. You might have been able to find the cause of the performance anomalies.Sabresiberian - Friday, June 3, 2005 - link
I find it hilarious that someone calling him- or herself 'porkster' is complaining about someone else's language :)Apple's computers have made their fame on their user-friendliness, so I think it is very appropriate to compare these computers with OSX on the Apples, as that's where the user-friendliness resides and both OSes are in the same family. It would have been fun to compare using the 64 bit Win XP Pro - I bet we would all get a good laugh out of that. Microsoft is determined, I think, to make a Linux man out of me yet :)
kresek - Friday, June 3, 2005 - link
waiting for AnandTech's YDL results, have a look at this:http://www-106.ibm.com/developerworks/library/l-yd...
SMOG - Friday, June 3, 2005 - link
#13 Thresher: "When it comes down to it, performance is important, but not the only reason people buy what they buy. I would say more often than not, the decision is made with only a modicum of logic."Your right, and those people didn't read this article, at best they read the first page then skipped to the last to see if he bashed Apple or not. This article was for those who want to know just what the power of the PowerPC actually is. This is a technical artical, not a buyers guide. This is science.
Good Job.
CU - Friday, June 3, 2005 - link
You mentioned most people don't use the Intel compiler, but it would have been nice to see it and also the windows compiler and the ibm compiler.