Hard Light Productions Forums
Off-Topic Discussion => General Discussion => Topic started by: redsniper on March 03, 2004, 05:39:53 pm
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... for about $100. I'm planning on getting a new comp soon and I'm wondering: what's a good CPU? Would it be better to go Pentium or Athlon? Right now I'm leaning towards the Athlon 2700 XP which I think gets a little over 2 Ghz. So, any suggestions, advice, horror stories...
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IMHO Athlon offers better value for money.
Athlon 2700XP is around 2.4GHZ clocked, IIRC. But just ignore that - GHz speed means very little nowadays in terms of relevant performance. A 2700 should be equiavlent to a P4 2.7GHz (based on the name), I think - but not exactly. IIRC some AMD chips have better int performance but worse FP than the equal rated (not speed, the 2700XP = 2.7GHz intel thing) intel chips.
I think..... ben a while since I lasted looked at this sort of stuff.
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This is how it was explained to me.
AMD pushes more data through per clock cycle, while Intel just pushes it through faster.
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Originally posted by HotSnoJ
This is how it was explained to me.
AMD pushes more data through per clock cycle, while Intel just pushes it through faster.
Well, firstly Hyperthreading is, IIRc, based on dual pipelining for parallel processing. i.e. you have to balance the loads on each pipeline to get a benefit, which is a bastard to do. the PS2 has a similar problem (it has 4 pipelines, I think)
Secondly, Intel have a habit of making very large pipelines with many stages. I believe it's 35 in the P4. Pipelining basically allows instruction execution to be divided into multiple clock cycles, so that the entire data poath is in use (i.e. while instruction 1 is using the ALU, instruction 2 can write the registers, etc).
Theoretically, this 'stepped' execution should allow one instruction to finish execution every clock cyle - hence giving the MHz rating. Theoretically, it should be much faster - i.e. a 4-stage pipeline is 4* faster than the same machine with no pielining (rough example).
Unfortunately, it doesn't work that way. Because instructions may be dependent on others, or use data that hasn't been written yet (by an incomplete instruction), 'Hazards' occur when inconsistencies develop. Hazards either require correction (which has a hardware overhead in terms of detection and fixing the hazard), or requiring the entire datapath (pipeline) be flushed and restarting.
Thus, pipelining has maximum effectiveness with about, IIRC, 8 stages. After 16 stages, performance actually begins to decline. eventually, the cost of hazards negates the benefit.
and the P4 pipeline is 35 stages long. Even with paralleleism and other such fancy stuff I don't know about, that's gotta be dodgy.
so why do it?
Simple, you can quote a higher MHz rating based on the theoretical maximum instruction throughput, and make your machine look better than it is. Hence why the ratio of actualimprovement to MHz difference is so misleading. Not to mention that the design gets hideously complicated and hard to manage through managing those hazards.
Now, I don;t know AMD's tactics. But, thanks to a ranting, intel hating yet very clever CAD (Comp Arch & Design) teacher, I know they're better at this design malarky.
:nod:
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AMD's Athlon XP are the best low to mainstream chips out there. I'd suggest an Athlon XP-M 2500+ if you're overclocking though. They're apparently even better at overclocking than the old JIUHB 1700+s.
I personally can't wait for Newcastle and Winchester, the new Athlon 64 cores. Integrated dual-channel memory that doesn't require ECC :)
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Definitely the AMD Athlon 2500+ Barton.
Overclocks like the P4 2.8C and only $80 on newegg.
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That's a great processor too, but the new Holy Grail of Overclocking is the XP-M 2500+ on the Barton core. Rumours are 2.7GHz on air.
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so an XP-M 2500 would be better than a 2700? I don't know a lot about overclocking and all so which is better by itself? I mean, 2700 is more than 2500... :p
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The XP 2700+ is a processor that runs 2.17 GHz stock, 13 x 166, with 256KB L2 cache and a stock voltage of about 1.6-1.65. If you get one, even with a great stepping, you're looking at limited overclocking potential, but it's a safer bet.
The XP-M 2500+ is actually a mobile processor, running at 14 x 133 stock (1.83 GHz), with 512KB of L2 cache. Currently, though, they appear to be the single best chip to overclock, thanks to their low stock voltage of about 1.4w.
There have been reports of getting about 2.7GHz on air with the XP-M. I'm betting that's probably 12.5 x 216. The best overclock you can expect from the 2700 is probably about 13 x 185.
Pricewise, they're exactly the same. So basically, you're betting on how well the chip overclocks. The standard 2500+, though, is also popular, running at 11 x 166 with 512KB of L2 cache.
EDIT: Did a bit of research. Hexus.net recently did a review of the XP-M, finding it overclocked to about 2.4 GHz at 1.8v. For comparison, my 2100+, which is basically the same as a 2700+, maxes out at 2.275 GHz with my current cooling setup, at about 1.85v. So you get about the same performance, actually, with a bit of an edge for the 2500+, mostly due to core limitations. The 2500+ will run cooler at stock though (lower clockspeed and lower voltage).
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well, I don't plan on doing any overclocking so I guess I'll go with the 2700. Thank you all.
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Make sure you pick up some decent PC2700 or PC3200 RAM. Crucial, Kingston, and Mushkin are all well know brand names. Also, your motherboard should be based on either the nForce 2 Ultra 400, nForce 2 400, or KT600 chipsets. All 3 are well-known, stable chipsets, with the Ultra having a bit of a performance advantage, but with the KT600 having superior memory compatibility, IIRC. Good brands for motherboards are Asus, Abit, and MSI.
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Originally posted by Grey Wolf 2009
There have been reports of getting about 2.7GHz on air with the XP-M. I'm betting that's probably 12.5 x 216. The best overclock you can expect from the 2700 is probably about 13 x 185.
At what temperature would that get?
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Umm.... With my Zalman cooler (it's either a 6000 or 6500, all copper) I'm pushing 60+ for my internal temp at 13 x 175. Of course, I have poor case ventilation and that's the internal temp, as opposed to the die temp you normally see, which would be in the low to mid 50s, I believe.
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What about for my computer? The MSI-6561, has a FSB up to 266mhz. Could I use that XP-M 2500? What would be the best processor for that one?
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You definitely should consider of getting an AMD64 3000+.
It's got the best performance/value ratio.
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But is it 266 FSB?
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Anyone wanna help with this? U guys are smart, dig into your little brains...
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I did a litte research on my motherboard, it sais it doesn't support any Thorton, Barton, or Applebred and only supports the Thoroughbred at 133 FSB.
http://www.msi.com.tw/program/products/mainboard/mbd/pro_mbd_cpu_support_detail.php?UID=13
Based on that, what to do? I know nothing of processors and want a good one that will last a while, plus overclocking might be nice.
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The athon 64s run at a 800Mhz FSB.
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http://www.smksuperstore.com/catalog/viewitem.asp?ID=7349
this one will work. but I don't think the XP-M will for two reasons:
1. It doesn't appear on the list of those that do work.
2. It runs 333FSB i think
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Red, can that be overclocked or something? Not that I have to, of course, but if I wanted to at some future.
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it probably could. But I wouldn't over clock anyprocessor personally.
I would just buy a new mother board processor.
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Originally posted by redmenace
The athon 64s run at a 800Mhz FSB.
Athlon 64s don't have a FSB... not in the traditional sense anyways.
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So what will work then? That 64 will or no? I'm going loopy again...
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they will not.
you need to read tomshardware.com sometime.
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Actually, don't read Tom's for processors. For nice, objective discussions, read Ace's. For up to the minute info, X-Bit and the Inquirer. Hexus isn't bad either.