Original URL: http://www.theregister.co.uk/2009/02/18/review_graphics_gigabyte_/

Gigabyte passively cooled Radeon 4850 card

How quieter does your GPU need to be?

By Leo Waldock

Posted in Hardware, 18th February 2009 09:02 GMT

Review We've been hugely impressed by the Radeon HD 4850 graphics card thanks to the balance it strikes between price and performance, and we firmly believe that, at £125, it's damn good value.

Gigabyte GV-R485MC-1GH

Gigabyte's GV-R485MC-1GH: double-slot design...

Pretty much our only reservation with the reference HD 4850 centres on the cooling package. The HD 4850's graphics chip employs 800 unified shaders that generate a fair amount of heat. AMD chose a single-slot design for the HD 4850 even though the dual-slot HD 4870 has an enormous cooler. The single-slot form-factor makes it easy to slip an HD 4850 into almost any PC, and there’s more good news: AMD has selected a gentle fan speed that makes the HD 4850 surprisingly quiet.

The combination of a slimline heatsink and low fan speed means that the heat produced by the HD 4850 gets trapped in the casing, and we concluded our original review by saying: "We’d give the HD 4850 the nod on this one despite its toasty hotness."

Gigabyte has decided that the cooling package on the HD 4850 could stand some improvement and the result is the GV-R485MC-1GH, which is passively cooled. The model code breaks down thus: GV for Gigabyte VGA; R485 denotes a Radeon HD 4850; MC stands for Multi-Core cooling; and 1GH refers to the 1GB of memory.

You can see an animation that explains the Multi-Core Cooling feature here, but our photos should make things clear enough.

Gigabyte GV-R485MC-1GH

...with some serious metal for passive cooling

One cooling core sits directly on top of the GPU, and there are two more cooling cores which are each connected to the main core by a pair of heatpipes. These cooling cores are quite sizeable affairs so Gigabyte has used a dual-slot design which means that this HD 4850 has a packaging envelope that's similar to an HD 4870. One of the coolers projects through the mounting bracket by a few millimetres but this looks like a means of supporting the cooler rather than a way of shedding heat into the air at the rear of the case.

A reference HD 4850 is clocked at 625MHz core and 2000MHz memory, but here Gigabyte has set the core speed at 640MHz and the 1GB of DDR 3 memory has a true clock speed of 960MHz and an effective speed of 1920MHz. Those are rather odd speeds as the core is faster than stock while the memory runs a touch slower than standard.

Gigabyte GV-R485MC-1GH

The card minus its monster cooler

We tested the graphics card on an ASRock X58 motherboard with an overclocked Intel Core i7 965 running at 3.75GHz and found that this combination of clock speeds means that the Gigabyte performs the same as a reference HD 4850. As it uses passive cooling, the Gigabyte was absolutely silent, but the reference HD 4850 is pretty darn quiet so the difference wasn’t as great as it might be.

The problem is that the temperature of the graphics chip on the Gigabyte was reported by AMD's Catalyst drivers as 101°C. Your reviewer doubted the veracity of this information and foolishly touched a finger to the passive cooler – ouch, ouch, ouch.

Gigabyte GV-R485MC-1GH

The other side of the cooler

The reference HD 4850 heats up to 80°C despite using an active cooler so it seems inexplicable that Gigabyte would think it could keep the HD 4850 under control with a passive cooler, no matter how big.

Power Draw Results

Gigabyte GV-R485MC-1GH - Power Draw

Power Draw in Watts (W)

Gigabyte GV-R485MC-1GH - Chart Key

3DMark Vantage Results

Gigabyte GV-R485MC-1GH - 3DMark Vantage

Longer bars are better

3DMark06 Results

Gigabyte GV-R485MC-1GH - 3DMark06

Longer bars are better

Gigabyte GV-R485MC-1GH - Chart Key

Far Cry 2 Results
1280 x 1024 - No AA

Gigabyte GV-R485MC-1GH - Far Cry 2

Longer bars are better

1920 x 1080 - 2x AA

Gigabyte GV-R485MC-1GH - Far Cry 2

Longer bars are better

1920 x 1080 - 8x AA

Gigabyte GV-R485MC-1GH - Far Cry 2

Longer bars are better

Gigabyte GV-R485MC-1GH - Chart Key

In fairness to Gigabyte, the GV-R485MC-1GH behaved during a run of 3DMark Vantage, but the levels of heat coming from the cooler were terrifying, and we didn’t have the heart to wait for a blue screen to occur. In a matter of moments, we had a £12 Noctua NF S12 case fan installed, and the temperature dropped to a constant 50°. Although the Noctua is relatively cheap and quiet, you may struggle to mount a case fan to blow on your graphics card unless you can install it in the side panel of your case.

GPU Temperature Results

Gigabyte GV-R485MC-1GH - Temperature

Chip surface temperature in Degrees Celcius

Gigabyte GV-R485MC-1GH - Chart Key

Once we had the Gigabyte under control, we got busy overclocking it and found that the Automated Clock Configuration utility in the Overdrive section of the Catalyst drivers allowed us to crank up the speeds to 725MHz/1150MHz (equivalent to 2300MHz). This was higher than the 690MHz/2286MHz that was allowed with the stock HD 4850 and it shows that the Samsung K4J10324QD-HJ1A memory will run significantly faster than its rated speed of 1000MHz.

The difference in performance between the two cards was minimal in 3DMark06 and 3DMark Vantage. The Gigabyte has a significantly better frame rate than the stock card in Far Cry 2 when you crank up the anti-aliasing but you're actually seeing the benefit of 1GB of memory compared with just 512MB on the stock card.

All in all, the Gigabyte HD 4850 has the same performance as a regular HD 4850 and it overclocks in much the same way, but the passive cooler is very bulky and you need to give some thought to cooling to make the system work.

Verdict

The Gigabyte R485MC-1GH is a reference HD 4850 with a socking great passive cooler. We feel that a case fan is an essential extra, so you’re paying at least £30 for the privilege solely of moving the heat around inside the case of your PC. ®

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