Introduction

GeForce FX 5700 Ultra GDDR-3 reference board

In our e-GeForce FX 5700 Ultra review, we mentioned that the GeForce FX 5700’s twin 64-bit memory controllers were unique in the sense that they supported up to 1GB of conventional DDR memory, DDR2, or GDDR-3 memory.

GDDR-3 (short for graphics double data rate-3) is a new memory type developed specifically for graphics. ATI and NVIDIA have been working closely with memory manufacturers throughout the development of GDDR-3. With GDDR-3 the focus is on power, not performance. GDDR-3 runs at a lower voltage than DDR2, allowing it to consume less power than older memory types (assuming clock speeds remain equal).

Can you spot the difference between the 5700Us?

Still dont see anything?

As a result, memory manufacturers can hit higher clock speeds more easily than if previous memory types had been used. Another added benefit is that board manufacturers can implement cards with more memory – a 512MB DDR or DDR-2 card would require more power circuitry and a more expensive board design than a 512MB GDDR-3 card would. In addition, GDDR-3 modules are available in higher densities than DDR-2: NVIDIA’s 128MB GeForce FX 5700 Ultra GDDR-3 board only requires four GDDR-3 memory modules; 128MB DDR-2 boards had eight memory modules (four on each side of the board). Therefore, the heatsink found on the bottom of GeForce FX 5700 Ultra DDR-2 boards isn’t necessary for GDDR-3 cards.

GDDR3 up top, DDR2 on the bottom with heatsink and memory

Micron was the first memory manufacturer to announce its GDDR-3 products, so we naturally assumed they’d be NVIDIA’s first choice. However, GDDR-3 modules from Samsung (part number K4J55323QF-GC20), the world’s largest memory manufacturer, are used on the GDDR-3 variant of GeForce FX 5700 Ultra.

Top of the reference card

Latency is a little higher for GDDR-3 than GDDR-2. To offset this, NVIDIA has increased the clock speed on their GDDR-3 boards to 475MHz (950MHz effective). This is an increase of 25MHz over the original DDR-2 based GeForce FX 5700 Ultra, and allows the board to at least equal the performance of its predecessor. We also found a few cases where performance actually improves by a few percentage points. This move is similar to the faster memory modules ATI integrated on its 256MB RADEON 9800 PRO boards, which utilized DDR-2 memory modules.

Price and availability

NVIDIA first began shipping GDDR-3 GeForce FX 5700 Ultra boards in February, so boards should begin hitting retail in the next few weeks. XFX was the first company to jump on to GDDR-3, announcing their board shortly after NVIDIA’s announcement, so they’re expected to be first to market with a retail sample. NVIDIA expects GeForce FX 5700 Ultra board prices to remain the same regardless of memory type used.

So with a GeForce FX 5700 Ultra GDDR-3 reference board from NVIDIA in hand, and a fresh copy of Unreal Tournament 2004, we were curious to see how the two 5700 Ultra boards stacked up to one another. As you can see, the board design on both cards is identical (other than the aforementioned memory layout/heatsink changes). But how about performance? Let’s take a look!