Linux and L2 Cache; Sempron vs. Athlon
by Kristopher Kubicki on August 18, 2004 2:29 AM EST- Posted in
- Linux
As AMD rolls out its newest Sempron processor line, many readers are asking us if the reduced cache Socket 754 Sempron 3100+ really compares with already shipping Athlon 64 single channel solutions. Today we take two single channel, 1.8GHz processors with differing L2 cache and compare them in the same Linux benchmarks we have used in the past. The Athlon 64 2800+ and the Sempron 3100+ are nearly identical processors, except for the 256KB cache difference. There is also a $20 delta between the two retail products, so today we decide if the $20 difference between the two processors is worth the sacrafice of level two cache and 64-bit addressing. We have provided benchmarks of another 1.8GHz 32-bit processor from AMD, as well as the Athlon 64 3000+ for reference only.
Update: This article got pushed live prematurely. If you read it before 12PM EST on the 18th, you read an incomplete, unfinished article.
| Performance Test Configuration | |
| Processor(s): | AMD Athlon 64 2800+ (130nm,
1.8GHz, 512KB L2 Cache) |
| RAM: | 2 x 512MB PC-3200 CL2 (400MHz) |
| Memory Timings: | Default |
| Motherboard: | Chaintech ZNF-250 (nForce3,
Socket 754) DFI NFII Infinity (nForce2, Socket 462) |
| Operating System(s): | SuSE 9.1 Professional (32 bit) Linux 2.6.4-52-default |
| Compiler: | linux:~ # gcc -v Reading specs from /usr/lib/gcc-lib/i586-suse-linux/3.3.3/specs Configured with: ../configure --enable-threads=posix --prefix=/usr --with-local-prefix=/usr/local --infodir=/usr/share/info --mandir=/usr/share/man --enable-languages=c,c++,f77,objc,java,ada --disable-checking --libdir=/usr/lib --enable-libgcj --with-gxx-include-dir=/usr/include/g++ --with-slibdir=/lib --with-system-zlib --enable-shared --enable-__cxa_atexit i586-suse-linux Thread model: posix gcc version 3.3.3 (SuSE Linux) |
| Libraries: | linux:~ # /lib/libc.so.6
GNU C Library stable release version 2.3.3 (20040405), by Roland McGrath et al.
Copyright (C) 2004 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.
There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A
PARTICULAR PURPOSE.
Configured for i686-suse-linux.
Compiled by GNU CC version 3.3.3 (SuSE Linux).
Compiled on a Linux 2.6.4 system on 2004-04-05.
Available extensions:
GNU libio by Per Bothner
crypt add-on version 2.1 by Michael Glad and others
linuxthreads-0.10 by Xavier Leroy
GNU Libidn by Simon Josefsson
NoVersion patch for broken glibc 2.0 binaries
BIND-8.2.3-T5B
libthread_db work sponsored by Alpha Processor Inc
NIS(YP)/NIS+ NSS modules 0.19 by Thorsten Kukuk
Thread-local storage support included.
Report bugs using the `glibcbug' script to |
Even though we are using 1GB of memory in a dual channel configuration, the Socket 754 platform will only perform in single channel mode. Fortunately for AMD, since the memory controller is directly on the processor we do not see large latencies going from dual channel to single channel mode. Only the Athlon 64 2800+ can run 64-bit binaries, so for the sake of experiment we will only look at 32-bit binaries today. We have looked at 32-bit versus 64-bit performance in the past, and we will revisit it again in a few weeks, so today we will just focus on 32-bit performance.
Also keep in mind the GCC 3.3.3 included with SuSE 9.1 Pro has many back ported options from the official 3.4.1 tree. Our results with GCC 3.3.3 are much more optimized than the standard GCC 3.3.3.
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- Saturday, October 24, 2009 - link
sell:nike shoes$32,ed hardy(items),jean$30,handbag$35,polo shirt$13,shox$34n0cmonkey - Friday, August 27, 2004 - link
HAHA! Still beaten by the VIA c3:[q]sempr0n
aes-128 cbc 48860.49k 50275.58k 51223.21k 51349.16k 51565.91k
[b]C3
aes-128-cbc 13090.59k 51065.12k 174593.45k 426600.92k 735548.02k[/b]
xp
aes-128 cbc 42891.92k 43746.44k 44291.99k 44433.72k 44470.25k
64 3000
aes-128 cbc 54463.69k 56014.76k 56781.82k 57404.76k 57005.40k[/q]
And that's on OpenBSD. ;)
balzi - Tuesday, August 24, 2004 - link
woo-hoo.. let it be known, persistence pays. I even think it's biblical -- gotta be good.KristopherKubicki - Monday, August 23, 2004 - link
Future-proofing is impossible :)But anyways, i am still going to stand by my conclusion; which was that for a 32-bit processor its worth the difference in price. I've got half a dozen machines here that are dying for the K8 architecture but dont need 64-bit; sempron is the better choice since it saves me money and doesnt cash me out for performance.
Kristopher
ThePlagiarmaster - Sunday, August 22, 2004 - link
KristopherI won't argue the 10% of a machine as a whole (you're right). But then you're talking about a completely different machine. I thought we were just talking about a choice between a machine with just two different chips with all other things being equal, just as in the article...The point was which chip to buy, not which computer. Right? In both of my posts I'm talking $16, not $100. In this case, a bit of future-proofing for a measly $16 is a VERY good thing.
I never mentioned anything about taking 10% from the whole machine (nor did I see that as a point in the article- I saw ONE config, with two different chips compared). Of course that's a huge difference and in that case the results wouldn't look like your article does which shows a pretty close run between the A64 2800+ and Sempron 3100.
Yes, as I just posted, Win64 looks like 1st half next year. Thats not years away (9 months tops). Once Win9x hit most of the games within 1yr were 32bit (only EA games lagged and still ran on dos for a while). If it's so far away, why are you running 64bit articles? How many 64bit chips do you think will be sold by next Xmas (Intel's selling them now, numbers should rise drastically within the next 15 months). We already know of some game makers saying 64bit is worth it, unreal being the front runner.
After looking here: http://www.xbitlabs.com/articles/cpu/display/athlo... I'm left wondering if any of your benchmarks are truly 64bit on 64bit OS. Look at RSA Decrypt, thats 4+ times faster! RSA Encrypt is 3+ Times faster! Gzip 2 times faster. Good increase in Divx too (15% or so isn't bad). AES encrypt/decrypt showing 50%+. The worst result I see in the chart for 32bit app+32bit OS vs. 64bit app and 64bit OS is 10%. Thats the WORST result. With a BETA OS that dates back to sept last year (machine only had 1GB of ram also) and beta drivers. Can't get any slower this next year can it? We know filters could show 57% improvement (AMD just showed this a few weeks back with the panorama deal and 47% with the other app Crafty Chess). How many people are buying digital cameras these days? Photo apps are getting easier and easier to use for newbs, filters are common even in the crappy lowend apps. We know the Sempron is slower than the 2800+, so comparing it in these benchmarks (as in xbitlabs) would show the sempron even worse.
Your own LAME/LINUX 32bit vs 64bit HERE: http://www.anandtech.com/cpuchipsets/showdoc.aspx?... shows a 34% improvement. Why doesn't your lame benchmarks now show this? Don't tell me MP3's aren't popular :) Your own quote in that article (well Anand himself quoted not YOU per se) "The performance improvement here is astounding - in 64-bit mode the Athlon 64 FX managed to finish the encode 34% quicker than in 32-bit mode, if these results are any hint of what could be in store for Windows users, there's a lot of promise behind the Athlon 64...assuming we get software support in time." So we have Encryption (up to 4x+ faster), MP3's (up to 34% faster), Divx (15% faster), Photo filter type crap (up to 57% faster), games (unreal makers say 64bit is faster, yes w/o 4GB+ memory too). What's left? Seems like you need to say $16 is worth it. If you are running 64bit Linux (I believe you are) and 64bit APPS ALSO (can't tell in article) then clearly linux needs work. Beta Win64 stuff shows huge benefits as shown above. I think I showed enough proof on win64 with 64bit above. So I end this here. Know more I can say, nor should I have to.
Viditor, yes (as anandtech confirmed in earlier sempron article) NXbit is on S754 variants, and NOT on S462 variants.
Viditor - Saturday, August 21, 2004 - link
Kris...it seems my question got lost. Does the Sempron have NX bit?KristopherKubicki - Saturday, August 21, 2004 - link
balzi: Working on it.Kristopher
KristopherKubicki - Saturday, August 21, 2004 - link
ThePlagiarmaster: My whole argument has been you get an Athlon XP with an onboard memory controller, and you'll see larger performance from the memory controller than the 64-bit things. Sure if 64-bit was here now, i would probably side even stronger with you.>If sales people would do their jobs, nobody would ever buy these things.
I disagree. 10% difference in price is not something to thwart at. There is a budget sector for a reason; I am sure YOU can afford the extra cost, but the fact of the matter is a lot of people cannot. If you could realistically shave 10% off every component in a computer, it becomes a difference between a $900 machine and a $1,000 machine - and those type of costs are significant.
The argument of "*only* 10% in cost" for features not needed for years still is not valid. Have you checked the last shipping date for Windows 64-bit lately?
Kristopher
ThePlagiarmaster - Saturday, August 21, 2004 - link
Viditor,Supposedly all S754 variants will have it. NONE of the S462's will. But I still can't see buying a sempron when we're only talking $20 for the real thing. Scratch that, $16 just checked Pricewatch. Pretty soon we'll be dealing with a lot more encrypted pages etc. Not to mention apps (filters are easily optimized) and games that will be 64bit friendly (no I'm not talking over 4gb needed here). In encryption and zipping alone we're talking more than 50% improvements. Some of the encryption stuff shows 2x-3x improvements. Why would anyone want a sempron? I guess I'm saying I have REAL problems with the conclusion in the article :) People should be told "PLEASE, buy the 64bit chip and forget Sempron - Do yourself a favor".
If AMD wanted a value chip they should have just made it a BIT slower, not turned off features that are VERY important. I can understand the AthlonXP version, they're trying to keep the socket alive for mainboard makers etc, but a disabled S754 version just sucks. In 6 months people will be saying, "damn, you mean I could have had all that for $16 more?". Lets also not forget that it is actually a FASTER chip for that $16 also. Not by much, but it is faster in everything. People only buy these things because they are completely uninformed about what they are LOSING by saving $16. If sales people would do their jobs, nobody would ever buy these things.
Viditor - Saturday, August 21, 2004 - link
Kris - Thanks for the article.About the conclusion, one point that wasn't mentioned (and that I have been unable to find info on) is whether or not the Sempron has NX bit?
If the answer is no, then that would be another benefit to going with the A64 2800+...