Introduction

Note: This article is an in-depth look at overclocking. We'll cover how to do it, what sort of performance you can achieve, problems and potential solutions, etc. Overclocking can be frustrating, rewarding, fun, and dangerous. We don't mean "burn the house down" dangerous, but you could certainly end up ruining some or all of your computer components. We take no responsibility for any difficulties or losses you may experience by using the information in this article, and we certainly take no responsibility for any damage that may occur to any person, place, or object. The manufacturers of the parts that we are using are also not accountable for any loss/damage that may occur - most companies void your warranty for overclocking. It's a risk, and it's your risk - proceed with caution. Finally, overclocking is never a "guaranteed result". You may or may not match the results that we achieve. We'll be happy to offer suggestions if you need them, as will many of our forum members. Patience and research are part of overclocking as well, so please understand that you may have to do some work on your own. If you can accept those warnings, we hope that you enjoy this article.

Back in the day, overclocking was in some ways simpler than what we see now. You would typically buy a mid-range processor and then try to increase the bus speeds as much as possible in order to get the most performance out of your system. Older Pentium chips also allowed you to change the multiplier, so with some luck, you might get your 2.5X multiplier on a Pentium 166 up to 3.0X, resulting in a 33 MHz overclock. Other than a few special chips like the Pentium M and Athlon FX, increasing multipliers is no longer possible. The modification of bus speeds can still be used, but it isn't necessarily the best or only way to try to overclock your system. We have mentioned overclocking performance in many articles, but we haven't taken the time to really explore all the options out there. We also know that current Intel and AMD setups have very different options and performance when overclocking is used, so we want to look at that as well.

Before we branch out into AMD vs. Intel comparisons, however, let's talk about the past top performers. The Celeron 300A is fondly remembered by many people, and with good reason. Yes, we have had some other good parts in the intervening years, like the 2.4 GHz Northwood cores, the low end Prescott cores, and the Athlon XP-M Barton parts. However, when you look at the 50% overclock of the Celeron 300A (and it wasn't just possible, it was common), none of the other parts have really ever approached that level of overclocking without some serious investment in cooling options. (Some people even managed to get the 300A to 504 MHz - an amazing 68% overclock!) Northwood's 2.4 GHz to 3.2 GHz is still an impressive 33% overclock. The 2.4 GHz to 3.6 GHz Prescott overclock (using the 2.4A) actually matches the 50% of the 300A, but you sacrifice some features (HyperThreading and high FSB speeds) with the lower model parts. Meanwhile, the overclocking darling that was the XP-M 2500+ "only" managed a typical overclock of 1.87 GHz to 2.4 GHz, a 29% overclock.

That brings us to the part that we're investigating today. It is arguably the best overclocking platform since the old Celeron 300A: AMD's Venice core. One thing that we didn't mention above is the role that price plays for many overclockers. Sure, the Athlon-FX can reach clock speeds and performance that most other chips only dream about, but at a cost of roughly $900 just for the processor, a lot of people will only read about it. What made the 300A so attractive was that it was not only a monster overclocking chip, but it cost around $150 and competed with $500 chips. That's why the 2.4C and 2.4A Pentium 4 are also well regarded; they cost under $200 and could compete with chips that cost two to three times as much. The price of entry for the cheapest Venice core (the 3000+) is once again very low; $120 for the OEM model, or $145 for the retail version.

We'll get into the details more in a moment, but for now, we'll just say that the 3200+ may actually be a better choice, and that's what we are using for this article. We are also using the retail model, and some people will say that retail parts tend to overclock better than the OEM chips. We'll simulate 3000+ overclocking using a 9X CPU multiplier, but that may or may not be an entirely accurate representation of 3000+ overclocking performance. In general, though, what we're hearing is that almost all of the Venice cores can run at very high clock speeds with a bit of effort, so there isn't a huge difference between 3000+ parts binned for 1.8 GHz and 3800+ parts binned for 2.4 GHz. AMD has simply set the package to use a maximum 9X multiplier on the former and a 12X multiplier on the latter. Talking about CPU multipliers leads us into the real meat of the discussion, though, so let's get into it.

The Overclocking Platform
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  • edlight - Tuesday, January 03, 2006 - link

    I've found a way to overclock and retain the Power Now/Cool'n'Quiet.

    I let the motherboard do it's Cool'n'Quiet thing but I don't load the AMD driver. I run CrystalCPUID, which lets me set up the multiplier and voltage of each of the 3 cpu steps.

    The voltage setting of the motherboard, for my Gigabyte, has to be on Auto for Crystal to be able to change it.

    The highest Crystal can go with my 1.4v 3000+ Winnie is 1.45v.

    This let me take it up to 3800+ -- a speed of 2.4. 240 x 10.

    So it's running at 1.2 -- 240 x 5 -- most of the time. I set it at 1.2v there and froze it there and p95'd it overnight, as I did to the other 2 speeds.

    For me this is a great compromise between running "cool 'n quiet" and high performance.

    It's only a small percentage speed jump to 2.6, but requires alot of voltage and heat.

    I can't say what the maximum voltage would be for a Venice. Crystal lets me choose higher voltages than 1.45, but it doesn't actually set them.
    Reply
  • RaulAssis - Wednesday, December 21, 2005 - link

    Some people reported that the Cool 'n' Quiet feature could work in a OC system. Maybe not all bioses support correct scaling of voltages when the system is OC and the Cool 'n' Quiet feature is turned on. Reply
  • JarredWalton - Wednesday, December 21, 2005 - link

    With any moderate OC, CnQ is going to cause problems. It dynamically adjusts multipliers and voltages... something that will usually screw up an overclocked system. I would strongly discourage trying to use CnQ with an OC'ed setup. Some motherboard BIOSes actually disable CnQ automatically if you enable overclocking features. Reply
  • mrmoti - Wednesday, November 30, 2005 - link

    If I understand correctly:

    Performance RAM running at DDR400 2-2-2-8 and Value RAM running at DDR400 2.5-3-3-8

    At same OC on the processor, Performance RAM outperformed the Value RAM by 5% to 10%, being the price something between 80% to 100% more.

    So, what's the impact of runnig faster memory at high lateny? Say DDR500 at 3-4-4-8

    Because looking at the table of estimated latencies, (Performance) DDR400 2-2-2-5 has an estimated latency of 46.5, where (Value) DDR400 2.5-3-3-7 has an estimated latency of 49.75, an improve of 6.5% being in the range of 5% to 10% better.

    By the same table, DDR500 3-4-4-8 has an estimated latency of 42.4, an improvement of 8.8% over the Performance DDR400 and 14.7% over the Value DDR400, based only in latencies.

    Can anybody run a benchmark confirming/denying this?

    Being the case that the price of DDR500 with those timings is in the middle between Performance and Value RAM
    Reply
  • T Rush - Sunday, October 16, 2005 - link

    One of the main focuses of this article seems to be value -vs- performance RAMs when over clocking, but you chose to run the performance RAM at settings where is doesn't perform, shame on you Jarred Walton, very disappointed

    If you look at the settings you used to test the two RAMs at...
    http://images.anandtech.com/reviews/cpu/amd/athlon...">http://images.anandtech.com/reviews/cpu...niceover...
    ...you see that the MAX speed you where able to run the OCZ Rev2 at was not in it's "performance envelope", as the OCZ Rev2 is one of the worst performers in this speed range http://www.anandtech.com/memory/showdoc.aspx?i=256...">http://www.anandtech.com/memory/showdoc.aspx?i=256... <OCZ Rev2 at 266MHz, and all the other "performance RAMs" beat it

    But if you look at how the OCX Rev2 does work at much higher speeds, where it does perform...
    http://www.anandtech.com/memory/showdoc.aspx?i=256...">http://www.anandtech.com/memory/showdoc.aspx?i=256...
    ...you find that it is performing much differently than what you tested at, and would have shown a much larger performance lead over the value RAM

    How did you get this on to Anandtech? How could you show such a bad comparison of value -vs- performance RAM on a site which has always shown so much information about how these RAMs perform?

    I not only blame you, but also the editors for not catching how badly you have managed to make performance RAM look. It is clear you were trying to prove that cheap RAM can falsely perform as well as high-end performance RAMs. If you truly wanted to show what performance RAM can do when over clocking you either needed to run the OCZ Rev2 at much faster speeds, or use a different performance RAM that works well at the sub 270MHz speeds you tested at.
    Reply
  • JarredWalton - Sunday, October 16, 2005 - link

    This is one set of RAM run through extensive tests on one platform. I've seen the same RAM run faster in some other systems, but not a whole lot. Just because some DIMMs reach DDR636 doesn't mean that all of them do. I could run this RAM at 3-4-4-8-2T timings at DDR600, but it actually ran worse than 2.5-3-3-8-1T with the lower memory ratio.

    What is clear is that I wasn't trying to "prove" anything. I was running some comparison tests with a system using two different types of RAM, and I'm sorry that you don't like the results. What I did prove was that someone one a budget could build a very fast system. An FX or San Diego core with higher quality RAM and a better motherboard would be better overall, but price/performance it would get stomped by this <$1000 setup.
    Reply
  • T Rush - Monday, October 17, 2005 - link

    I don't find the OCZ Rev2 to be a good example of the high performance RAM everyone thinks it is, as it doesn’t perform well at the speeds you (and most everyone else) use…not compared to other good over clocking RAMs
    Granted some of the other performance RAMs do cost much more than the value RAMs, and even more than the OCZ Rev2, but they would have shown a greater performance difference than the value RAM which in your tests was not able to run any faster than its stock rated speeds or timings
    Your testing shows that running RAM at faster speeds adds very little performance over stock speed value RAM, and that is because the timings/speed relationships of that peculiar performance RAM at those peculiar higher speeds were not good.
    As I said before, all the other performance RAMs beat it, and perform much better at speeds under 270MHz than the OCZ Rev2 does

    Using the right RAM at the right speeds to run the best timings is the true art to over clocking, as RAM timings and speeds can allow the AMD64 to perform at much higher levels when over clocked

    I do not disagree with your results, as that is how those RAMs perform:
    Value RAM only being able to run its rated speeds and timings, not being able to over clock at all.
    OCZ Rev2 running at higher speeds but with such bad timings that it shows very little performance gains unless you are able to run it at CAS 2.5 in the 300MHz range

    I am not a fan of the OCZ Rev2 because of this, but I am a fan of performance RAM over value RAM, even on a budget system.

    If you read clue22’s reply “so basically what the everybody is saying about the value RAM vs. low latency more expensive RAM is that for the athlon 64 it is basically a waste of money (i.e. you only get about 5% performance gain), but usually spend 100% or more money to get the "better" RAM.”
    …and cyptonomicon’s “and its nice to see those ram comparisons. good to see those results on the latest a64 platform and confirm once again that the ram makes only a few percentage points difference”
    …next intellon’s “I understand how/why the memory quality is not too imoprtant (5-9% increase for 100 bucks = not worthy)”

    Clearly by using the OCZ Rev2 you did not show what spending a little bit more for better performing RAM can do. You have shown that running RAM at speeds with timings where it doesn’t perform well is a waste of money, but this does not answer any questions about value -vs- performance RAM
    Reply
  • JarredWalton - Monday, October 17, 2005 - link

    I've got X2 benchmarks with four different types of RAM in the works:

    OCZ VX
    OCZ Plat Rev2 (TCCD)
    Mushkin Value
    PDP 2x1GB 2-3-2-5-1T

    Other than the fact that 2GB of RAM helps out certain tasks (BF2 load times!), the total performance difference with those configurations is still not huge. With a 3.5V RAM voltage, the VX would do better, but even then the difference isn't above 10%.
    Reply
  • T Rush - Thursday, October 20, 2005 - link

    for a budget system I would say the socket 754 is better...as the motherboards and CPUs are cheaper...and you can get ClawHammer CPUs with the larger performance 1MB L2 cache
    the only thing you miss out on with the 754 is the dual channel memory mode(which only adds very little performance anyway)...but by over clocking the core:memory speed you can easily match the performance gained by the greater bandwidth of the dual channel mode (this could be why the socket 939 doesn't show large gains from overclocking with the memory 'in-sync'..as it can't use all the bandwidth the faster memory gives)

    with a mid-range system you could pick a 10X multi 3200+ Venice, or even a 11X multi 3500+ Venice(either of those would have a much better CPU multi for overclocking than the 3000+'s 9X multi) which would allow you to keep the HTT/HTL speed at a more reasonable level(270MHz and 245MHz to reach 2.7GHz CPU speed...where a 9X multi CPU would need a 300MHz HTT speed to run the CPU that fast)
    ...but the 3200+ and 3500+ are costing $190 to $250...so for not much more you could have a performance San Diego core on the 939 platform (3700+ 11X multi SD is only $267 now)
    ...so for $80 to $40 more I would go for the larger San Diego core...I would also spend the ~$20 more for CAS 2 RAM (over $90 Value RAM)...thats like just $100...for a computer with much better parts...and say you use this system for 18 months, that works out to less than $6 a month for a using higher quality parts
    Reply
  • Deathcharge - Saturday, October 15, 2005 - link

    Jarred this was a great article and did come at a great time as i am in the market for buying a bang for the buck system. One thing you didnt mention (although i saw that in the CPU-z screen shots) is the CPU stepping

    http://www.amdcompare.com/us-en/desktop/default.as...">http://www.amdcompare.com/us-en/desktop/default.as...

    the 3200+ venice core comes in 3 different stepping and i belive the one you used in your article is the E3 stepping which is being replaced with the E6 stepping. Any info on how well the new stepping OC? initial reports from around the net indicate that it doesnt OC very well for some reason would love to read your comments on this.

    Do you know if it is possible to OC to 2500 or 2600O with stock HSF as i would really like to save the money spent on the TT-90 and get a 7800GT (as opposed to x800xl). one final thing would OCZ value VX require active cooling?

    thanks and keep up the good work, really enjoyed reading it and would look forward to future articles
    Reply

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