Athlon 64 Revision E: Unofficial DDR500 Support
by Anand Lal Shimpi on July 11, 2005 12:05 AM EST- Posted in
- CPUs
High Speed Dual Core + New Memory Dividers
We’ll start off with the Athlon 64 X2 4800+.Featuring a 2.4GHz core clock, the 4800+ doesn’t necessarily meet our high clock speed requirement for needing a faster memory bus. Each core also features a 1MB L2 cache, which reduces its dependency on a higher speed memory bus. However, we are dealing with a dual core CPU here - which means that situations where both cores are being used are more likely to increase the chip’s memory bandwidth needs. Because of this, we’ll focus on improvements in multithreaded or multitasking environments, as well as looking at single threaded performance to measure the impact of the faster memory clocks.
According to our table of supported DDR frequencies by the DFI board, the 2.4GHz 4800+ gives us two options above DDR400 - mainly, 218MHz and 240MHz, or an unofficial DDR436 and DDR480, respectively.
Theoretical Memory Bandwidth Comparison
Just to make sure that these new dividers were actually doing something, we used the final 32-bit version of ScienceMark 2.0 to confirm that there were tangible increases in memory bandwidth:| Memory Speed | ScienceMark 2.0 Memory Bandwidth (MB/s) | % Improvement over DDR400 |
| DDR400 | 5378.08 | N/A |
| DDR436 | 5495.33 | 2% |
| DDR480 | 5851.52 | 9% |
With DDR436 offering only a 2% increase in peak theoretical memory bandwidth over DDR400, our only hopes for a performance increase are with the much higher bandwidth settings - i.e. DDR480.
Multimedia Content Creation Winstone 2004
Business applications barely made any use of the dual channel memory bus of Socket-939 CPUs, so we had no expectations to see any sort of performance boost from these new DDR speeds in tests like Business Winstone. Thus, we turn to Multimedia Content Creation Winstone 2004, whose Lightwave test is multithreaded and does take advantage of the X2’s dual core setup:| Memory Speed | MMCC Winstone 2004 | % Improvement over DDR400 |
| DDR400 | 41.9 | N/A |
| DDR436 | 42.3 | 1% |
| DDR480 | 42.7 | 2% |
The biggest performance difference that we see here is 2%, which is less than the 3% variation that we can see between test runs in this particular benchmark.
3D Rendering
3D rendering is another area where we see good use of dual core processors, but these tests also showed us a 0 - 1% increase in performance when comparing DDR480 to DDR400:| Memory Speed | 3dsmax 6 - SPECapc Rendering Composite | % Improvement over DDR400 |
| DDR400 | 2.78 | N/A |
| DDR436 | 2.8 | 1% |
| DDR480 | 2.8 | 1% |
| Memory Speed | Cinebench 2003 | % Improvement over DDR400 |
| DDR400 | 636 | N/A |
| DDR436 | 639 | 0% |
| DDR480 | 641 | 1% |
Even SPECviewperf 8 barely showed any performance increase (from 0 - 2%), and that suite of applications tends to be quite dependent on memory performance.
Video Encoding
DivX and Windows Media encoding tests have always been very memory bandwidth sensitive. Let’s take a look at the impact of the new memory dividers there:| Memory Speed | DivX 6 + AutoGK | % Improvement over DDR400 |
| DDR400 | 50.6 | N/A |
| DDR436 | 51.3 | 1% |
| DDR480 | 53.2 | 5% |
With a 5% improvement in performance, DivX 6 gives us the first indication of any truly tangible performance increases due to the higher DDR speeds unofficially supported by the new chips.
| Memory Speed | Windows Media Encoder 9 (fps) | % Improvement over DDR400 |
| DDR400 | 4.22 | N/A |
| DDR436 | 4.24 | 0% |
| DDR480 | 4.28 | 1% |
The same success isn’t seen in our WME test, with a 0 and 1% increase in performance at DDR436 and DDR480, respectively.
Gaming
Doom 3 is also a very good measure of the impact of memory bandwidth, as are most other 3D games:| Memory Speed | Doom 3 (1024 x 768 fps) | % Improvement over DDR400 |
| DDR400 | 121.9 | N/A |
| DDR436 | 124.3 | 2% |
| DDR480 | 127.2 | 4% |
Finally we see another situation where there’s a positive impact in memory performance. Here, DDR480 gives the X2 a 4% increase in frame rate at 1024 x 768. However, cranking the resolution up to 1600 x 1200 cuts that improvement down to 1%. The usefulness of the 10x7 numbers is in simulating situations where you are less GPU bound.
Overall, we’d say that there’s not that big of an improvement from using DDR480 with the Athlon 64 X2 4800+. The biggest performance boosts will occur in video encoding and games where you are not GPU bound, and even then, you should expect an increase in the 3% - 5% range.
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Murthunder - Wednesday, July 13, 2005 - link
So what is the best memory for good overclocks yet is still stable? I originally tried a pair of Corsair TWINX1024-4000 Pro XMS sticks and my DFI LANParty UT nForce4 Ultra-D board would fail to post. I swapped the XMS for two 512MB sticks of Kingston ValueRam DDR333 c2.5 and my board has been stable ever since and faster than anything else I have. Any suggestions for an OC newbie who can't afford to simply keep trying different sticks until something works?Myrandex - Tuesday, July 12, 2005 - link
An interesting comparison would be an Athlon64 w/ DDR500 and a close to equivilently clocked Athlon64 w/ the HTT running at 250 to make the memory DDR500.semo - Tuesday, July 12, 2005 - link
#32, man if i could get those here in the uk (at that price).so Zebo, what do you mean that you can't run a64 in sync with memory. for example: if i get those:
http://www.ebuyer.com/customer/products/index.html...
and a dfi lanparty ultra d with a 3000 venice, would i be able to get a decent overclock?
Zebo - Monday, July 11, 2005 - link
It's really a shame anand did'nt do 3-3-3 like 99% of PC4200 sold runs @ 250...PrinceGaz - Monday, July 11, 2005 - link
Quite right Zebo, what this shows is that even the dual-core A64 processors when running multiple threads get little benefit from faster memory even at the same tight timings. Also as you say there is no such thing as a synchronous memory speed that might provide a performance advantage, as all memory speeds are in reality a divider from the CPU core speed. Running good PC3200 memory at or as much as it'll go above DDR400 2-2-2 is probably the best option. And if you want 2GB, get 2x 1GB modules so you can still run them at 1T command-rate as that's a better bet than four single-sided 512MB modules.One thing to bear in mind is if you enable Cool 'n' Quiet, that the memory may actually run faster at the lower CPU multipliers when it is set to other than DDR400 in the BIOS (DDR400 ensures the memory divider is always equal to the CPU multiplier).
Zebo - Monday, July 11, 2005 - link
http://forums.anandtech.com/messageview.aspx?catid...512 sticks
www.newegg.com/Product/Product.asp?Item=N82E16820146532
1024 sticks
www.newegg.com/Product/Product.asp?Item=N82E16820146545
#31 -- sure at a price, in the case of UTT is a pretty serious one if you ask me.. high volts.. high noise from fans.. high cost.. which may not be best usage of funds.. maybe that $150 saved is better spent on 7800GTX instead of 6800Ultra..or something like that.
AdamK47 3DS - Monday, July 11, 2005 - link
I'm a long time overclocker so a couple percent faster means something. If the option is there and it runs stable then go for it. All these little percentages add up in a heavily tweaked system. Overclocking the video, CPU, memory, and bus can all add up.Zebo - Monday, July 11, 2005 - link
PS I recommend Crucial sticks (not the 8T).. they have micron G abord..same as Ballistix for half price (but not speed binned so no guarantees).. Search around though.. many many including myself hit 2-2-2 with both 1024 x 2 and 512 x 2 configs.Zebo - Monday, July 11, 2005 - link
1. Keep in mind anand kept 2-2-2, low latency up to 250Mhz and *still* saw little difference.. fact is only one type, well two if you include anceint but still the best BH-5, can run this bandwidth and latency, Windbond UTT. This ram seems failure prone, watchout! The volts required, eg 3.5+, to attain those LL and bandwidth are extremely dangerous without active cooling on the ram. This ram is also "untested" (UTT) from windbond adding in an extra layer of uncertainty...Add in 2-3x the cost of regualar value muskin/corsiar/OCZ/Crucial which *can* all hit 2-2-2@200 with ~2.8V make this choice pretty lame considering the marginal payoffs. If you like cyber olympics and compete on the margins 0-5% by all means go for it...but 99% of y'all could find much better application of your funds.2. All other high bandwidth ram run crappy timings @ 250Mhz which will get stomped by LL @ 200. I've shown in forums you basically need 100mhz extra (not even 50) to hang with 200Mhz 2-2-2 when running ram 3-4-3, aka loose timings. Not worth buyin the high bandwidth stuff either when value muskin/corsiar/OCZ/Crucial which *can* all hit 2-2-2@200 with ~2.8V.
3. Overclcokers who want to run 1:1... there is no such thing as 1:1 in A64 archtecture.. all memory run async. So no problemo, no performance hit using 166/150/133 memsetting with value muskin/corsiar/OCZ/Crucial and shooting for 2-2-2@200 while clocking CPU to high heaven with proper HTT/FSB adjustments.
4. We see why AMD is'nt dieing for DDR2 this last year+.. and *when* they finally jump on board it will be at 667 instead of 533Mhz.. They can't afford the performance hit 533 will give, I'd be very surprised if 667 DDR2 is faster for AMD unless you run Crucials which is capable of 3-2-2.
In sum -- don't believe the hype. Get good cheap safe X2/A64 and DDR -- you'll be fast for a very long time.
robster3323 - Monday, July 11, 2005 - link
Is it possible to measure this stuff on a multi socket board? One of AMD's big selling points of HyperTransport is that other CPU's in other sockets can get to other memory faster. I wonder what impact these faster memories would have on socket to socket memory access?In other words socket one is direct connected to mem slot 1, the data in mem slot one is needed by a CPU in socket two, transiting the Hypertransport. How much benefit do the faster memories present?