DDR2 vs DDR3: The Battle of Latency vs. Bandwidth - Asus P5K3 Deluxe WiFi & Corsair TWIN3X2048-1333C9DHX Review

Author: William Henning
Editor: Howard Ha
Publish Date: Thursday, July 5th, 2007
Originally Published on Neoseeker (http://www.neoseeker.com)
Article Link: http://www.neoseeker.com/Articles/Hardware/Reviews/ddr2_vs_ddr3/
Copyright Neo Era Media, Inc. - please do not redistribute or use for commercial purposes.

Today we are going to take a look at a new DDR3 motherboard, and a new DDR3 memory module - but before we do that, let's take a quick look at how we got here...

In the beginning, there was static ram - and it was good - however each bit of memory needed six transistors, limiting how many bits could be implemented on a chip, and they thus dynamic ram was invented. Dynamic ram only needed a single transistor and a single capacitor for each bit,  so it could be a lot denser - packing around three times as many bits per square millimeter as static ram.

Dynamic ram then lead to double data rate dynamic ram. Eventually, DDR evolved to DDR2 - then war broke out... fought on two great battlefields. They were upon the fields of Latency and the oceans of Bandwidth.

Initially, DDR had vastly better latency than DDR2, and was not very far behind on bandwidth. It looked like DDR2 might lose the war.

But wait.

As processes were improved, DDR2 was able to reach greater heights in the all mighty MegaHertz ranks. DDR2-667's were able to hold their own against DDR-400. DDR2-800 started to take the lead... and then DDR2 low latency memories started to appear. The once strong DDR began to falter.

Eventually, the DDR camp had to admit defeat... DDR2-1066 5-5-5-15 was too much for it to compete against... and with DDR2-1111 low latency memories coming in later.. well, the less said, the better. And there was peace for a while, as DDR2 dominated.

Now, the reign of DDR2 has a challenger. DDR3 -  and we get a stong sense of Deja Vu (or is our memory playing tricks on us again?). 

And that brings us to today. What we have now is DDR3 boasting higher Megahertz ratings than DDR2 - but at the expense of increased latency.  The familiar struggle continues, and many of you will have noticed in my past articles the importance of balancing latency and higher frequencies to achieve overall maximum performance.  Let's see how early DDR3 modules manage this balance.

The best available JEDEC standard DDR3 modules are DDR3-1333 at 9-9-9-24 timings... a far cry from the best low latency DDR2-1111 4-4-4-12 timings - not to mention the DDR2-1250 5-5-5-15 modules almost matching DDR3 in speeds with still much lower latencies and I think history will repeat itself. The DDR2 camp may currently be laughing at the feeble latency and performance of the low end DDR3-1066 9-9-9-24 modules, but then later realizing that DDR3-1333 may be the point of parity - and that DDR2's doom may well be sealed by DDR3-1600 and above.

Let's see what we can find out about existing modules.

DDR2 and DDR3 are both memory technologies that attempt to provide computers with high bandwidth memory.

As manufacturers have pushed DDR2 well beyond its originally intended PC2-6400 (800MHz effective data rate) and since there does not appear to be any letup in the "need for speed", memory manufacturers have started making DDR3 devices in order to far surpass the bandwidth they can easily get from DDR2 devices - and reduce power consumption and heat generation at the same time.

As DDR2 frequencies went up, so did the voltages required to perform at the higher data rates - and of course this caused ever more heat to be generated. Heatspreaders became heat sinks... then came optional fans... and some manufacturers went so far as to mount water blocks on the DIMM's!

Now that DDR3's run at lower voltages - they generate less heat.

In our lab we are fortunate enough to have some excellent DDR2 memory devices, and to make the test even more interesting, we have DDR2 and DDR3 versions of the (essentially) same Asus P5K / P5K3 Deluxe WiFi AP motherboard. In our recent review of the Asus P5K Deluxe WiFi, we found it to be an excellent performer - and the P35 chipset appears to provide good performance for enthusiast boards.

But enough of that for now... let's look at the new DDR3 capable Asus P5K3 Deluxe WiFi, and the Corsair TWIN3X-2048 1333C9DHX modules!

Representing DDR3 technologies, we have the new Asus P5K3 Deluxe WiFi AP and the Corsair TWIN3X2048-1333C9DHX. 

Representing DDR2 technologies, we have the new Asus P5K Deluxe WiFi AP and the Corsair's TWIN2X2048-8888.

To make the comparison as fair as we could, we kept everything we could the same - so we are using the Asus P5K Deluxe WiFi AP motherboard we've reviewed, along with the excellent Corsair XMS2x2048 PC-8888 4-4-4-12 modules for comparison - pitting some of the best low latency DDR2 modules from the same manufacturer against their new high speed DDR3 modules.

In order to keep this article to a managable size, I'd like to refer you to our Asus P5K Deluxe WiFi AP review for more details of the Asus P5K3 Deluxe WiFi AP motherboard as well; that board is the DDR2 version of the board used in this review, with the only significant differences being DDR2 vs. DDR3 support, two extra SATA2 cables, a small fan, and the more impressive heatpipe & coolers on the P5K3. I will of course cover the overclocking capabilites of this board separately in this article :-)

As you can see from the photo below, the P5K3 Deluxe WiFi has a SERIOUS number of heatpipes and heatsinks on it. Initially I was worried that our Noctua 12 coolers would not fit due to the sheer size of the heatpipes/heatsinks - but fortunately the cooler fit just fine.

All the attention paid to cooling was a promising sign for getting good overclocks out of the board.

Here is a closer look at all that cooling near the processor. Notice all the solid state capacitors too.

The Southbridge needs less cooling, but it still gets a heatpipe assist. I like how the SATA connectors were grouped, and the position of the IDE connector is also decent.

Next, we see a lot of thought has been given to I/O expansion capabilities. You can see the tiny Asus WiFi card on the top right side of the left image; and you can also see the blue PCIe 16x slot for a GPU, and the black PCIe 4x slot (with 16x connector) for a second GPU or high bandwidth PCIe card. Two PCIe 1x and three PCI slots complete the picture; for a total of seven expansion slots.

The I/O backpanel has a PS/2 keyboard connector, but wisely foregoes a PS/2 mouse connector for two USB connectors - most mice are USB based these days, and one can never have enough USB2 ports! Two gigabit Ethernet connectors, another four USB2, two eSATA, one FireWire six audio connectors and one WiFi antenna jack complete the picture.

I thought it was worth showing the eight voltage regulators on the back of the board.

Here we can see the DDR3 sockets, the ATX power connector, and the obsolete floppy connector.

As you can see, there is little difference in the physical DIMM slots between DDR2 and DDR3.

The only difference between the motherboards is the type of memory socket they use and a slight difference in the heat pipes. We even used the same E6400 processor, hard drive, video card, power supply etc. for the comparison - the only variable is the memory (and the slight difference in the BIOS for accomodating DDR3 vs. DDR2)

 

 

The Corsair XMS3 DDR3 memory is officially the "Corsair TWIN3X2048-1333C9DHX"

Naturally, "TWIN3X" stands for DDR3 dual channel kit, and 1333C9 means 1333MHz data rate with CAS 9 latency - but what does DHX refer to?

The shot below from the Corsair site tries to explain it...

DHX stands for "Dual Heat Xchange" (the marketing people swallowed an 'e') and basically refers to how heat is drawn away from the memory chips - mostly through the heat spreaders mounted on the outside, but also with some heat being transferred through the soldered ball grid array pads to the PC board, and convection cooling - air moving around the chip. If you want to read more about DHX, here's an application note on Corsair's site.

Ok, the modules look sharp, and they did clamp a couple of small heatsinks to the PCB itself... but what you and I want to know is how it performs!

One of the reasons this article is titled "DDR2 vs. DDR3" is that it is the first time we've reviewed DDR3 motherboards and memory - fortunately by using a DDR2 version of the same board, the DDR2 / DDR3 comparison is as fair as we can make it. We will also be testing DDR3 motherboards and memory modules from this time onwards.

Test Setup 

We made the test systems as similar as we could, other than the memory - so it should give us some very interesting results!

Hardware for testing of the Asus P5K Deluxe WiFi:

Hardware for testing of the Asus P5K3 Deluxe WiFi:

 

Benchmarks Used

For now, here is a listing of the tests performed:

Video drivers used were the NVIDIA ForceWare version 93.71 package.

"Cry havoc and let slip the dogs of war..."

Business Winstone

With this benchmark, we try to evaluate how well DDR2 and DDR3 will work for office applications. As you can see, DDR3-1069 fares poorly compared to low latency DDR2-800; and DDR3-1333 fares poorly compared with DDR2-1066.

When overclocked, DDR3-1552 did quite well.

Content Creation

For content creation, the DDR3-1069 results are slightly worse than the DDR2 800; however DDR3-1552 results pretty close to the DDR2 results.

 

 

HDTach

The HDTach scores were basically the same on both boards, regardless of DDR2 vs. DDR3 or clock rates.

WinRAR

DDR3-1066 was beaten by DDR2-800, DDR3-1333 managed to beat DDR2-800.

Low latency DDR2-1066 slaughtered DDR3-1333 - but DDR3-1552 managed to beat all the DDR2 scores in this comparison.

RightMark Read

DDR3-1333 at 9-9-9-24 is badly beaten by DDR2-1066 at 4-4-4-12. On the other hand.. overclocking the DDR3 memory we got some great results at DDR3-1552 at 9-7-7-18 timing!

RightMark Write

Pretty much the same story as with reads. DDR3 starts to be competitive at 1333MHz, and starts looking good at 1500+ MHz.

RightMark Latency

As I expected; the DDR3 memory at less than 1333MHz had horrible read latency, however once you hit 1552MHz, it did quite well.

RightMark Bandwidth

The Corsair PC3-1333 did quite well at the standard PC3-1333 9-9-9-24 setting, and did extremely well when overclocked to 1552 9-7-7-18!

 

Sandra CPU

No surprises here; the charts are ordered by processor speed, memory speed does not make a huge difference to Sandra CPU.

Sandra Bandwidth

For Sandra Bandwidth, the PC3-1333 results are slightly slower than the DDR2-1066 low latency results; and the overclocked PC3-1552 results are simply outstanding!

 

 

 

 

Lame MP3

Looks like LAME is perfectly happy with DDR3 memory with a fast FSB, but really does not like slow FSB & DDR3 at low processor clock rates.

TMPGEnc

DDR3 PC3-1333 did well for TMPGEnc video encoding, and ran neck to neck races for performance champion...

Xvid

Given that Xvid and TMPGEnc are similar applications, we should not be surprised that the relative standings stayed the same!

Halo

DDR3-1333 performs almost as well as low latency DDR2-1066, and again, DDR3-1552 performs well.

Jedi Knight

Pretty much the same story as with Halo.

Unreal Tournament

Nothing new here.

Doom 3

Doom 3 may be an old benchmark, but I still really like it.

We keep seeing the same result - DDR3-1333 is just a bit slower than very low latency DDR2-1066; and that DDR3 starts to take off at over 1500MHz. The less we say about the performance of DDR3 at under 1333MHz the better, and I cannot in good conscience recommend that anyone get DDR3 memory at lower speeds than 1333MHz

Quake 4

Quake 4 is a bit more latency bound than Doom 3, but as we've observed, DDR3-1333 performs well.

Overclocking

The Motherboard:

The best stable overclock we were able to achieve on the P5K3 Deluxe WiFi was 485MHz FSB with a 7x multiplier.

We were able to post, and even run some programs with a 500MHz FSB, but it was simply not up to our standards of stability; however you should not be dissapointed, a 485MHz FSB is still 45.6% faster than the officially supported 1333MHz FSB, and even 21.2% faster than the next touted FSB speed - 1600MHz.

What I found interesting is that there was little need to increase Vcore to get major FSB speed increases - perhaps it has something to do with all those solid state capacitors, the eight voltage regulators on the back - or perhaps the BIOS is setting higher than reported voltages. Whatever the reason, we got some very high overclocks at relatively low Vcore settings.

The DDR3 Memory:

The Corsair 1333MHz DDR3 memory performed above my expectations. DDR3 is causing the same type of transition that DDR2 did - increasing latencies and bandwidth. What most people don't realize is that the increased latencies work out to be about the same as DDR2 latencies when the increases in data transfer clock rate are worked into the equation.

As you can see from the table below, a higher FSB, processor speed, and lower latency lets the same memory running at a lower data transfer rate handily beat itself at 1600MHz.

CPU Clock 3.2GHz 3.395GHz 6.10%
System FSB 1600Mhz  1940Mhz 21%
Mem Speed 1600Mhz  1552 -3%
Timings 9-9-9-24 9-7-7-18  
WinRAR 753 784 4.12%
WinRAR MT 1501 1558 3.80%
Doom 3 251.2 258.5 2.91%
Sandra CPU int 29622 31411 6.04%
Sandra CPU fp 19894 21082 5.97%
Sandra Mem int 7745 8709 12.45%
Sandra Mem fp 7763 8715 12.26%
Sandra Latency 71 69 2.82%
RMMA read  9048.66 9716.05 7.38%
RMMA write 7212.44 8760.24 21.46%
RMMA latency 53.39 50.24 5.90%
RMMA bw max 6345.09 7045.42 11.04%
CineBench 47.7 44.8 6.08%
CineBench MT 25.9 24.7 4.63%

Basically, as a simple example, if you had DDR2-667 memory with 5-5-5-15 timing, that would have exactly the same latency as DDR3-1333 memory with 10-10-10-30 timing, as the latency clock cycles had to go up to compensate for the higher transfer rates because there is no magic.

DDR3 is basically DDR2 with an extra level of interleaving on the memory modules, and just because it can clock out the data faster, it does not mean that they managed to increase the basic RAS, CAS and other latencies... and since they are now specified relative to a higher speed clock, the number of cycles for specifying latencies get larger.

 

The results of our tests show that DDR3 can hold its own against good DDR2 memory - low latency PC2-8500 - at PC3-10667 speeds. The results also show that once DDR3-1600 memories are released, they will eclipse the speed of all but the highest rated specialty low latency DDR2 modules.

The problem with DDR3 is that currently it is difficult to justify spending far more on DDR3-1333 modules than on low latency DDR2-1066 which will give you better overall performance. There is no question in my mind that DDR3 will surpass DDR2 in performance once DDR3-1600 and DDR3-2000 hit the market, but that time has not yet arrived.

Mind you, the Corsair modules performed extremely well, and if you purchase motherboards requiring DDR3 modules you most certainly cannot go wrong with getting some of these modules - as you saw, they performed far beyond their rated specifications, and when overclocked, turned in very impressive numbers.

Conclusion

The Motherboard:

The Asus P5K3 Deluxe WiFi is a solid P35 implementation with quite good overclocking abilities. I liked the plethora of I/O available, and the heat pipe system seemed to work very well. Frankly, I was a bit surprised that I could not get the system stable at a 500MHz FSB, but a future BIOS update may fix that, and 485MHz FSB is nothing to sneeze at. I liked how stable the board was with low Vcore and Vram settings.

The DDR3 Memory:

The Corsair TWIN3X-1333C9DHX memory turned out to be a better performer than I thought it would be based on some of the DDR3 naysayers opinions; and Corsair is being very conservative with its 9-9-9-24 SPD timings as the memory ran fine at 9-7-7-18 at up to 1552MHz - as a matter of fact, I was able to reach 1600MHz at 9-9-9-24. Given how well it performed, I am sure it won't be that long before Corsair starts making even faster, lower latency, DDR3 modules.

The Battle:

DDR3 has arrived, and it is here to stay - and the first DDR3 motherboard we have examined performs well.

Currently, the battle rages all around... and DDR2 is winning more battles than it is losing... but the writing is on the wall. I believe that for the next six months or so, DDR2 will still dominate, but its reign is over.

Once the memory module manufacturers start working their magic, and compete on high speed lower latency DDR3, it will come into its own, and it will dominate the landscape until it is unseated itself by a future contender.

DDR3-1333 is a decent buy; DDR3-1600+ will start to take the performance crown away from DDR2.

Regardless, some things are obvious... both the DDR2 and DDR3 versions of the Asus P5K/P5K3 Deluxe WiFi are excellent boards; and you can't go wrong with high end memory - regardless of it being high end DDR2 or high end DDR3.

Look at your application mix, the benchmark results, and your budget, and make the choice that is right for you.

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