Date: Tue, 17 Apr 2001 16:20:23 -0700 From: "Jeremiah Gowdy" <jgowdy@home.com> To: "Linh Pham" <lplist@closedsrc.org>, "Vincent Poy" <vince@oahu.WURLDLINK.NET> Cc: "Kris Kennaway" <kris@obsecurity.org>, "Marc W" <mwlist@lanfear.com>, "Kyle" <freebsd@sysmach.com>, <questions@FreeBSD.ORG> Subject: Re: the AMD factor in FreeBSD Message-ID: <002c01c0c795$15bee360$015778d8@sherline.net> References: <Pine.BSF.4.33.0104171507100.44584-100000@q.closedsrc.org>
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> On 2001-04-17, Vincent Poy scribbled: > > # Thanks for the insight but what about in a Single CPU environment? > > The AMD Athlon tends to beat the Pentium III in most cases (when > matching Mhz... faster Athlons will fly by a Pentium III without a > problem). The Pentium 4 tends to beat the Athlon in memory bandwidth > intensive cases (ie: MPEG-4 encoding, some streaming media apps) and in > Quake III (that's because the Q3 code is heavily optimized for the P3/P4 > processors anyways). This is not entirely true. Although the P4 has a 400mhz bus speed, actual testing shows that the Pentium 4 puts out almost the same throughput as it's 100/133mhz counterparts, it simply takes more clocks to do so. The applications in which the Pentium 4 wins are SSE/SSE2 optimized. These are not all that common. If you're referring to MPEG-4 encoding as tested in Tom's Hardware, remember that the Pentium 4 got the crap kicked out of it in the non-SSE2 non-3DNow! optimized version of the test, and since the application wouldn't even BE SSE2 optimized if it weren't for Intel not liking the results of the benchmark, I don't really care much for the Intel optimized benchmark. If Intel were going to go around and optimize EVERYONE's software, that would be another story. Not to mention the fact that the Pentium 4 clocks down as the processor heats up, causing a Pentium 4 1.5ghz to run at 750 mhz when the load is 100% (1.0) for an extended period of time. No wonder the Pentium 4 1.5 ghz loses head to head with an Athlon 1.2 ghz in non-Intel optimized testing. The processor speed steps like a laptop depending on the power/heat conditions. Even calling such a cpu a 1.5 ghz is a stretch in my opinion with that underclocking. The P4 will run at 1.5 ghz when idle, but then clock down to 750 mhz when the load is 1.0. What the heck is the point of that ?! It's more than happy to burn away power idling at 1.5 ghz, but when the processor is actually needed to get some work done, it has to underclock to avoid overheating. "1.5 ghz, except when you need it." http://slashdot.org/article.pl?sid=01/04/13/2041238&mode=thread http://www.inqst.com/articles/p4bandwidth/p4bandwidthmain.htm As for the AMD+SMP vs Intel+SMP, I can't say regarding the FreeBSD support, however, AMD's SMP is supposed to be far faster than Intel's because it has a Point-to-Point bus for the SMP connection, meaning _each_ CPU has a dedicated 200mhz (100mhz DDR) connection to the bus, when on an Intel SMP motherboard the two or more cpus will share the same 100mhz bus. That means on a 4 way SMP Intel system, each cpu will get an effective 25mhz access to the bus under full load in theory. By the same theory, AMD cpus would each have their own 200mhz dedicated connection to the bus, even in an 8 cpu setup. AMD cpus support up to 14 way SMP. The PIII can only support 2 cpus, and the Xeon can only support 4. http://www.sandpile.org I won't even start on the Pentium 4's Rambus RDRAM stupidity. Also it seems important to mention, current pricewatch.com prices: Athlon 1.33 ghz $216 Athlon 1.2 ghz $190 Pentium 4 1.5 ghz $454 Pentium 4 1.4 ghz $288 Pentium 3 1.0 ghz $217 Considering the Athlon 1.2 beats the Pentium 4 1.5 ghz in honest non-Intel biased x86 processing (like business applications which aren't really optimized by SSE2 or 3D-Now!), I see no reason to pay that much for a Pentium 4. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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