Radeon HD 4870 X2 and Crossfire review

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6 - Setting up the PC - Noise | Heat | power Consumption

Setting up the PC

Installing the X2 into your system will be a pretty easy job. Just slide the card into a free PCIe slot, connect one 6-pin and one 8-pin power connector to the card (if one is missing, the card will not work). I expect AIBs to include a 6 to 8-pin power converter cable by the way. I do recommend you to just buy a high-end PSU with both connectors on there anyway. Cable management alone would make that look much nicer. Bare in mind though that the board is lengthy, 27 CM. Make sure nothing is blocking/obstructing the product.

Once the card is installed we startup windows. We installed our driver, rebooted and that was it. With a single X2 there's no need to tag Crossfire active in the drivers or anything. The card will work straight out of the box. Just the way we like it.

Quick and easy.

Power consumption

It's time to do some actual testing with these card. We'll start off by showing you some tests we have done on overall power consumption of the PC. Looking at it from a performance versus wattage point of view, the power consumption is really good with the new 55nm products.

Our test system contains a Core 2 Duo E8400 Processor @ 3.0 GHz (FSB 1333), the ASUS P5E3 Deluxe mainboard, stock cooling on the CPU, DVD-rom and a WD Raptor drive. The results:


System Under FULL load

Radeon HD 4850 269 Watt
Radeon HD 4870 334 Watt
Radeon HD 4850 Crossfire (2) 421 Watt
Radeon HD 4870 X2 (R700) 437 Watt
Radeon HD 4870 Crossfire (2) 480 Watt
Radeon HD 4870 X2 (R700) Crossfire 740 Watt

The monitoring device is reporting a maximum system wattage peak at 437 Watts with 2-way 4870 embedded on the X2. Two in Crossfire is seriously scary at a near 740 Watts !

Power supply wise I recommend at the very least, 600 Watts. You might not utilize all that power distribution, yet especially in this high-end game make sure you have some reserves folks. You do not want your PSU to run at it's maximum all of the time. See, it's not that your PC will consume that much power, it's just that you want to make sure your PSU can deal with the hefty load and will stay stable during you entire gaming experience.

Please make note of the fact that the card uses one 6-pin PCIe power connector and one 8-pin connector.

Inevitably people will opt CrossfireX and go with a 4-GPU based model. With two cards obviously 1000+ Watt power supplies are recommended, and in fact even needed to be able to even supply something as simple as enough PCIe graphics power connectors. We passed 700 Watts, which is just too much to play games folks. We used a Galaxy 1000 Watt DDX PSU by the way, perfectly stable.

There are many good PSU's available, over the years we reviewed a lot of them and have loads of recommended PSU's for you to check out in there, have a look. Things that can happen if your PSU can't cope with the load?:

  • bad 3D performance
  • crashing games
  • spontaneous reset or imminent shutdown of the PC
  • freezes during gameplay
  • PSU overload can cause it to break down

The thermal envelope

Our Rivatuner application currently is under development for more precise thermal monitoring, yet we were able to monitor heat levels from both GPUs pretty well.

Temperature in degrees C Idle Peak
R700 GPU-1 65 87
R700 GPU-2 63 86

Our new PowerColor 4870 X2 sample has power management active, opposed to the sample we tested earlier on. Idle temps are roughly 65 Degrees C, yet when the GPU was fully utilized & stressed it reached nearly 90 Degrees C. I'll have to be honest here; the peak thermals on the entire 4800 series are just high. Obviously the product can take it fine, it just scares the living daylights out of me.

The good thing with the X2 is that the cooler is dual-slot, and uses the colder air inside your PC to cool down the GPUs and then blows it away (exhausts) it at the rear of the card, outside of the PC.

By the way, a LOT of heat is disposed outside the PC by the 4870 X2. Here's something to think about. If you game long enough in Crossfire, a small room will actually warm up. I'm not kidding.

Volume Levels

When graphics cards produce a lot of heat, that heat usually needs to be transported away from the hot core as fast as possible. Often you'll see massive active fan solutions that can indeed get rid of the heat, yet all the fans these days make the PC a noisy son of a gun. I'm doing a little try-out today with noise monitoring, so basically the test we do is extremely subjective. We bought a certified dBA meter and will start measuring how many dBA originate from the PC. Why is this subjective, you ask? Well, there is always noise in the background, from the streets, from the HD, PSU fan etc etc, so this is by a mile or two not a precise measurement. You could only achieve objective measurement in a sound test chamber.

The human hearing system has different sensitivities at different frequencies. This means that the perception of noise is not at all equal at every frequency. Noise with significant measured levels (in dB) at high or low frequencies will not be as annoying as it would be when its energy is concentrated in the middle frequencies. In other words, the measured noise levels in dB will not reflect the actual human perception of the loudness of the noise. That's why we measure the dBa level. A specific circuit is added to the sound level meter to correct its reading in regard to this concept. This reading is the noise level in dBA. The letter A is added to indicate the correction that was made in the measurement. Frequencies below 1kHz and above 6kHz are attenuated, where as frequencies between 1kHz and 6kHz are amplified by the A weighting. 

Jet takeoff (200 feet) 120 dBA  
Construction Site 110 dBA Intolerable
Shout (5 feet) 100 dBA  
Heavy truck (50 feet) 90 dBA Very noisy
Urban street 80 dBA  
Automobile interior 70 dBA Noisy
Normal conversation (3 feet) 60 dBA  
Office, classroom 50 dBA Moderate
Living room 40 dBA  
Bedroom at night 30 dBA Quiet
Broadcast studio 20 dBA  
Rustling leaves 10 dBA Barely audible

We start up a benchmark and leave it running for a while. The fan rotational speed remains constant. We take the dBA meter, move away 75 CM and then aim the device at the active fan on the graphics card.

Noise levels are becoming pretty standard these days, again we see both the coolers from the two products make more noise once it needs to cool down more (RPM spins up) though audible it's not bad though.

At idle you'll hardly hear the card, the FAN RPM is pretty low and results in an overall DBA level of less than 40, which is actually great. The minute though the GPUs start to heat up, the RPM of the fan will increase and you can expect roughly 43-44 DBa when the GPU is fully stressed for both cards.

So you'll likely you'll hear the fan blowing during gaming, but really .. not too loud at all.

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