The main advantage DDR2 has over good ole DDR memory is that it runs on a lower voltage, which lowers the power requirements, and allows it to scale higher with a small latency penalty.

GDDR3 (Graphics Double Data Rate3) takes this one step further, requiring less voltage than DDR2, and scaling even futher (though with some latency penalty). While the motherboard industry is making the transition from DDR to DDR2 memory, right now GDDR3 is only used on graphics cards. There are no current plans to migrate GDDR3 to the motherboard level - but who knows what the situation will be a year or two down the road. GDDR3 and DDR2 do share one thing in common, they are only packaged in BGA modules - leaving the old TSOP-II to be finally retired.

Micron were first out of the gate with GDDR3 DRAM modules, but the memory found on the Albatron GeForceFX 5700 Ultra is actually using Samsung K4J55323QF-GC20 GDDR3 DRAM. Compared to the Samsung K4N26323AE-GC22 DDR2 DRAM modules we find on earlier cards, the Samsung GDDR3 memory requires just 2.0V compared to 2.5V for DDR2. This which should help ease up on power consumption. However, as GDDR3 RAM runs with an even higher latency than DDR2, nVIDIA have had to clock the memory 50 MHz higher as well. This should offset any performance penalty that GDDR3 has over DDR2.

Overclocking the FX5700U3!

As usual we started with the core overclocking first; from 450 MHz we slowly went up a few MHz at a time. The core was a pretty good overclocker and the FX5700U3 went all the way up to 571 MHz before it started to have any problems. Anything higher though, and the computer would lock up when running any 3D application.

Since this is the first time we've dealt with GDDR3 we really don't know what to expect from the memory... but with 2ns DRAM we were hoping to hit some nice speeds. By default the memory is clocked at 950 MHz, 50 MHz higher than regular GeForceFX 5700 Ultra DDR2 based videocards. This is done to make up for a small latency penalty.

Not surprisingly we were able to crack the 1 GHz mark quite easily, but we were not able to go much higher than that. The maximum speed the FX5700U3 memory reached 1.02 GHz - if we tried to go higher we'd be greeted by artifacts like in the Raiders of the Lost Arc... you remember the big artifacts that spit out poison tipped darts, gigantic rock bowling balls, and all that fun stuff? Same thing here. :-)

PCStats Test System Specs:

processor: intel pentium 4 3.0c clock speed: 15 x 200 mhz = 3.0 ghz motherboards: gigabyte 8knxp, i875p videocard: ati radeon 9800xt ati radeon 9800 pro ati radeon 9700 pro asus radeon 9600xt msi fx5950 ultra-td128 msi fx5900u-vtd256 msi fx5900xt-vtd128 gigabyte gv-nv57u128d albatron geforcefx 5700 u3 memory: 2x 256mb corsair twinx 3200ll hard drive: 40gb wd special ed cdrom: nec 52x cd-rom powersupply: vantec stealth 470w software setup windowsxp build 2600 intel inf 5.02.1012 catalyst 3.9 detonator 53.03 workstation benchmarks 3dmark2001se codecreatures aquamark aquamark3 gun metal 2 x2 the threat ut2003 aa test, af and aa+af test 3dmark2001se x2 the threat ut2003