Investigations into Socket 939 Athlon 64 Overclocking
by Jarred Walton on October 3, 2005 4:35 PM EST- Posted in
- CPUs
Memory Options
Memory has been a major part of overclocking since we shifted to locked CPU multipliers back in the Athlon/Pentium III era. With the move to DDR RAM on the Athlon and Pentium 4, it has become even more important. Since all processors other than the Athlon FX chips (and Pentium M) are multiplier locked - at least on the high end of the scale - increasing your CPU clock speed means that you have to increase the system/CPU bus speed. If your default bus speed is 200 MHz and you have a 10X multiplier, you end up with a 2000 MHz processor. Raising the bus speed to 220 MHz would give you a 2200 MHz CPU, but it would also require memory that could run at DDR440 speeds. That's the way it normally works, and so we have unofficial memory speeds of up to PC4400 (DDR550) that allow you to overclock your bus, CPU, and RAM beyond the standard specification.
However, there are alternative methods of overclocking that may not require ultra high speed RAM. High speed RAM generally costs quite a bit more, and if your goal in overclocking is to get higher performance without spending a lot more money, doubling the cost of RAM defeats that purpose. We'll be looking at the impact of using the lower memory ratios in order to keep standard PC3200 at or below DDR400 MHz speeds. This means that you could use any PC3200 memory. There will be some performance loss, but the question is: how much? That's what benchmarks are for...
On the other end of the RAM spectrum, we find the high performance and high cost parts. Yes, you can buy some untested DIMMs with similar ratings to the high performance RAM for less money, but we're more interested in exploring guaranteed RAM speeds in this article, so we won't be taking that route. However, even if you can't reach the RAM speed that you want, our value RAM will serve as a minimum performance metric. At the high end, there are a few major contenders.
First, there's the high performance, high voltage RAM like OCZ VX and Mushkin Redline. (They probably use Winbond CH5 blanks, and we'll just use CH5 to refer to this memory from here on out. We could be wrong on the actual chips used, however.) You'll need a motherboard that can supply up to 3.5V to the RAM to get the most out of such memory, with 2-2-2-6 1T timings possible for as high as DDR533, give or take. You'll also want to get active cooling on the memory if you go this route. The next option is to grab some of the re-released Winbond BH5 DIMMs, which are similar to CH5 in that high voltages allow for 2-2-2-7 1T timings up to DDR500 speeds. The price and performance of these two options are roughly equivalent, with the CH5 generally reaching somewhat higher speeds. The drawback of CH5 is that it also requires at least 3.0V just to run at 2-2-2 timings and DDR400 speeds, where BH5 can do the same with only 2.6V. The final option is to go for the tried-and-true Samsung TCCD (or TCC5) DIMMs. You'll sacrifice some performance and have to lower the timings as RAM speeds increase, but the good news is that you won't need more than 2.80 to 2.90V to reach maximum clock speeds. You can also get TCCD DIMMs up to DDR600 and even beyond, which serves to counterbalance the better timings of BH5/CH5. The cost of Samsung TCCD is roughly the same as the other two choices.
So, which RAM do you choose? There are several factors, and in order to keep the number of benchmarks from rapidly bloating, we only used one type of value RAM and one of the performance RAM options.
For our high end RAM, we used what we already had available: OCZ Rev. 2 Platinum (TCCD memory as opposed to the newer TCC5 memory). One of the benefits of this RAM is that it doesn't run as hot as the BH5 and CH5 when overclocked, so active cooling won't be required at maximum clock speeds. Active cooling means more noise from your PC, and while few overclocked systems are truly quiet (without resorting to water cooling), many people will agree that adding more fans to the case isn't really desirable. This doesn't mean that BH5 or CH5 is a bad choice, and in many instances, either would be slightly faster than TCCx RAM.
The final pieces of the overclocking puzzle are the choice of case and power supply. Case selection influences (to a large degree) the number and arrangement of fans that you can use for cooling, though anyone with a bit of skill and a Dremel tool can add extra fans if needed. We'll talk a bit about heat sinks and fans for CPU cooling as well. First, let's start with the power supply, as it is more directly comparable to the components that we've covered so far.
Memory has been a major part of overclocking since we shifted to locked CPU multipliers back in the Athlon/Pentium III era. With the move to DDR RAM on the Athlon and Pentium 4, it has become even more important. Since all processors other than the Athlon FX chips (and Pentium M) are multiplier locked - at least on the high end of the scale - increasing your CPU clock speed means that you have to increase the system/CPU bus speed. If your default bus speed is 200 MHz and you have a 10X multiplier, you end up with a 2000 MHz processor. Raising the bus speed to 220 MHz would give you a 2200 MHz CPU, but it would also require memory that could run at DDR440 speeds. That's the way it normally works, and so we have unofficial memory speeds of up to PC4400 (DDR550) that allow you to overclock your bus, CPU, and RAM beyond the standard specification.
However, there are alternative methods of overclocking that may not require ultra high speed RAM. High speed RAM generally costs quite a bit more, and if your goal in overclocking is to get higher performance without spending a lot more money, doubling the cost of RAM defeats that purpose. We'll be looking at the impact of using the lower memory ratios in order to keep standard PC3200 at or below DDR400 MHz speeds. This means that you could use any PC3200 memory. There will be some performance loss, but the question is: how much? That's what benchmarks are for...
On the other end of the RAM spectrum, we find the high performance and high cost parts. Yes, you can buy some untested DIMMs with similar ratings to the high performance RAM for less money, but we're more interested in exploring guaranteed RAM speeds in this article, so we won't be taking that route. However, even if you can't reach the RAM speed that you want, our value RAM will serve as a minimum performance metric. At the high end, there are a few major contenders.
First, there's the high performance, high voltage RAM like OCZ VX and Mushkin Redline. (They probably use Winbond CH5 blanks, and we'll just use CH5 to refer to this memory from here on out. We could be wrong on the actual chips used, however.) You'll need a motherboard that can supply up to 3.5V to the RAM to get the most out of such memory, with 2-2-2-6 1T timings possible for as high as DDR533, give or take. You'll also want to get active cooling on the memory if you go this route. The next option is to grab some of the re-released Winbond BH5 DIMMs, which are similar to CH5 in that high voltages allow for 2-2-2-7 1T timings up to DDR500 speeds. The price and performance of these two options are roughly equivalent, with the CH5 generally reaching somewhat higher speeds. The drawback of CH5 is that it also requires at least 3.0V just to run at 2-2-2 timings and DDR400 speeds, where BH5 can do the same with only 2.6V. The final option is to go for the tried-and-true Samsung TCCD (or TCC5) DIMMs. You'll sacrifice some performance and have to lower the timings as RAM speeds increase, but the good news is that you won't need more than 2.80 to 2.90V to reach maximum clock speeds. You can also get TCCD DIMMs up to DDR600 and even beyond, which serves to counterbalance the better timings of BH5/CH5. The cost of Samsung TCCD is roughly the same as the other two choices.
So, which RAM do you choose? There are several factors, and in order to keep the number of benchmarks from rapidly bloating, we only used one type of value RAM and one of the performance RAM options.
Clck to enlarge.
For our high end RAM, we used what we already had available: OCZ Rev. 2 Platinum (TCCD memory as opposed to the newer TCC5 memory). One of the benefits of this RAM is that it doesn't run as hot as the BH5 and CH5 when overclocked, so active cooling won't be required at maximum clock speeds. Active cooling means more noise from your PC, and while few overclocked systems are truly quiet (without resorting to water cooling), many people will agree that adding more fans to the case isn't really desirable. This doesn't mean that BH5 or CH5 is a bad choice, and in many instances, either would be slightly faster than TCCx RAM.
The final pieces of the overclocking puzzle are the choice of case and power supply. Case selection influences (to a large degree) the number and arrangement of fans that you can use for cooling, though anyone with a bit of skill and a Dremel tool can add extra fans if needed. We'll talk a bit about heat sinks and fans for CPU cooling as well. First, let's start with the power supply, as it is more directly comparable to the components that we've covered so far.
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Deathcharge - Saturday, October 15, 2005 - link
also what do you think of opteron 144 or 146? the 144 are very cheap and they OC quite well apprentlypmorcos - Thursday, October 13, 2005 - link
Before I comment, you should know that I have been overclocking for 8 years now and literally overclocked all but one of the chips you mentioned in the beginning of this very good article. The HT multiplier was new to me with my most recent DFI NF4-SLI-DR board so I found that extremely useful and plan to see if I can up my speeds...but I digress.I think it would be extremely valuable to TRY to put in words the order with which an overclocker should approach making changes to settings. In other words, which is likely to be the most limiting/critical aspect(s) and from there tweak the others to max the system out.
It would be interesting to say, for example, that you start with a "safe" power settings (which is pretty obviously the limiting factor). For example, let's say your CPU and memory are rated at 1.3 and 2.8 V respectively. Why not go straight to "safe" settings for the two and tweak from there? It seems that the most useful piece of information that is NOT provided by anandtech or anyone else for that matter is a voltage and temp graph of stability/viability for these chips. It would be simple to take 3 samples (at a cost) of each chip and run the test with "average" cooling and find out what is "safe". For example if running all stock settings but upping voltages to say 2.4/3.6 V in the example above, you might see stability up to 1.65 / 3.1 V with the parts catching fire at say 1.8/3.3 V or stable at temp readings for cpu/memory of 44/47C but unstable above that. Once armed with these two graphs of information averaged from 3 chips tested the rest is very straight forward.
You simply set the cpu volts to 1.65 and memory to 3.1 V (the safe settings; check real voltages vis bios monitoring) and now you up your fsb and tweak your memory timings and in a few minutes you are running max.
Why do I think this is more valuable that showing us a graph of your results? Because like many I'm squeemish about upping the voltage on my processor and memory. I'm worried much more about the power-on affects than I am the "long-term" effects.
In computers, there are no long-terms for an overclocker. An overclocker's comp is 60% hardware and 40% software. Their greatest joy is in posting results on their favorite forum. I want to know that when I hit the power button...that the 1.7V setting does NOT have a 10% chance of blowing my processor.
My ramblings. Thanks again for another great article from by far the VERY BEST place in the world to find out how computer parts work.
JarredWalton - Thursday, October 13, 2005 - link
Thanks pmorcos.I'm working on the X2 3800+ OC followup, and I've gone back and done further testing of temperatures and voltages. Chips differ, so the real advice I have on that subject is to test your own chip extensively. I've heard of people doing 2.8 GHz on 1.500V with the Venice chips, but mine won't even POST at those settings. I think 1.65 or 1.70V was required to POST, and even then I couldn't run stable benchmarks without more voltage.
I will also be trying to cover a bit more of the "how to" process in the next one. Consider this the foundation, and the next article will refine the approach a bit. Your comments on what you'd like to see more of are definitely welcome, though, and I'll try to address the order and approach I take next.
Concerning another comment: "I want to know that when I hit the power button...that the 1.7V setting does NOT have a 10% chance of blowing my processor." I'm not quite sure I understand the concern or know how to test that. Are you saying that the power on process has more voltage fluctuations and may therefore toast the CPU in the first second? (I haven't had that happen over the past several months of testing this chip and others in overclocked setups.) I must admit that I'm extremely nervous about the 1.850V I used for running at 2.80 GHz, but even then the chip continued to function (for now - heheh).
Cheers!
Jarred Walton
WhipperSnapper - Thursday, October 13, 2005 - link
That was one of the best computer enthusiast website articles that I've read in a long time, but perhaps I don't get around too much. I'd like to hear more about the problems that spilled over to other components, such as the SATA hard drive (mentioned in the Final Thoughts) and whether or not the overclocking can be isolated to the CPU and RAM. I also wondered if there was a reason why you guys used a SATA hard drive and not an IDE drive and whether overclocking requires a SATA hard drive. (I don't see why it would.)
Also, have you guys tried to do any tests using memory stick heatsinks? Do they actually do anything? That subject might make for a worthwhile article on its own--RAM cooling.
aptinio - Saturday, October 8, 2005 - link
bravo! great article. very informative but not too bloated. can't wait to finally upgrade my amd k6-II with 1mb l3 cache on the motherboard! lol!Kougar7 - Thursday, October 6, 2005 - link
Thank you for the excellent, comprehensive, and very thorough article! :-) It must have taken a massive amount of work and time to complete. It’s answered my recent musings about my own Crucial value ram, which looks much nicer now! It’s also solved a question about OCing with recent AMD 64 chips, amongst also correcting a few personal misconceptions I’ve had.I just wish to ask if you plan to include a similar article on OCing with P4s? I personally run a 2.8C (Northwood) @ 3.4 rock solid at the 3.4C’s default voltage, but am now wondering exactly what performance hits, if any, that I’ve taken from having to use a 5:4 CPU:DRAM ratio instead of the previous 1:1, even though I’ve kept it at DDR390 and the timings better than specs.
I’m planning to bench the differences from a 1:1 ratio, a 3:2 ratio at highest speed I can get (sub-DDR333), my current setup, and finally one other setting where I got the value memory to run 2-2-2-6 timings, to get a more solid idea on which performs best with some solid figures.
Although the core and the platform itself both have both changed, I’d still be interested in a Intel processor based test! Perhaps instead of a P4, maybe a Pentium “D” OCing article similar to what you have planned with the X2 3800+? ;-)
I’m very much looking forward to your X2 3800+ OCing review!! You rock :-D Thanks in advance for it!
JarredWalton - Thursday, October 6, 2005 - link
I'm trying to get a socket 775 motherboard that will overclock well with Pentium D 820. Once I get that, I can give it a go. I've also got a Pentium 4 505 and a 540 that I want to run some similar tests on. First, though, I need an appropriate motherboard.clue22 - Thursday, October 6, 2005 - link
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. i have to build a couple of systems pretty soon and now i believe that my money would be better spent on 2GB of value RAM vs. 1GB of the more expensive stuff. does anyone know of a test that has been run with 2.5-3-3-8-1t vs. 2-2-2-5-1t? also why does every mid-range/gaming/hot-rod price guide ever recommend the either the samsung tccd (or tcc5) or winbond bh5/ch5 based memory if it has so little effect on performance. finally is it even important anymore (if it ever was) to get matched pairs of memory that are bundled together (supposedly manufactured at the same time)? i was looking at some corsair (had good experience with them in the past) xms3200xl RAM but now i think i should get more of their value select memory instead.thanks
RupertS - Wednesday, October 26, 2005 - link
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 moneyThis may not be a general rule.
It may just be that at this stage of development for GPU's, CPU's and memory, memory has more than enough capacity - it is not the choke point. If GPU and CPU speed were to improve while memory speed stayed the same, you might reach the point where increasing GPU and CPU speed was non-productive for games, while overclocking memory provided large performance improvements.
rabbit fighter - Wednesday, October 5, 2005 - link
Where was this explained? He said the 3200 was better in the first paragraph and that he would explain later, but I can't find the later explanation!