ASUS HD7850 DirectCU II TOP Review

[siopao1984]

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Built with AMD Southern Island's 'Pitcairn Pro' GPU, ASUS HD7850 DirectCU II TOP 2GB (HD7850-DC2T-2GD5) is a dual slot card with their much heralded "DirectCU II" direct contact heatpipe cooler.

At first glance from the front, the dual fan ASUS card looks similar size wise to the reference HD7850 blower design.

But when we turn the cards around, we see that the ASUS card actually uses a significantly cut down version of the reference PCB.

No changes at the display outputs so six monitor Eyefinity can be achieved with pair of mini-DP, a single HDMI and a DVI-D port.

The PCB is actually 8-inches length wise but the protuding part of the cooler extends it to 10.5-inches. We feel that there is a missed opportunity here to serve users of space constrained enclosures since the rated TDP of the HD 7850 at 130W is not very high anyway and can make do with a smaller cooling system. A 6-pin PCIe extension cable is preinstalled as the release catch on the card is obstructed by the cooler.

Accessories - the mandatory driver CD and instruction manual, a CrossfireX bridge and a DVI to analog convertor

Quick refresher - the HD 7850 has 16 'Graphics Core Next' compute units (almost half that of the big daddy HD 7970), with 1024 Stream processors, 32 ROPs and a GDDR5 256bit memory bus. ASUS pre-overclocked their card to 975MHz on the core and 1250MHz on the memory, a decent increase of 115MHz (13.4%) and 50MHz (4%) respectively. As with all the new 28nm based cards launching this year, the HD 7850 has PCIe 3.0 support, which helps in transfer bandwidth constrained scenarios like HD video encoding and will work with the current Intel Sandy Bridge-E and the upcoming Ivy Bridge platforms.

Read more: ASUS HD7850 DirectCU II TOP Review by VR-Zone.com

[siopao1984]

After removing the cooler, we actually see a pretty looking PCB. There is a black metal plate to prevent the PCB from warping, although we can't figure out why since the card is already rather short and the cooler is not very heavy.



The 'Pitcarn Pro' HD 7850 die, rotated 45 degrees with a surrounding metal shim. Interestingly the etchings shows that it is made in China, which means TSMC (or some other fab we're not aware of) must have a new 28nm facility there.





Eight 256MB Hynix BGA GDDR5 modules clocked at 1250MHz (5000MHz QDR).





Only a single 6-pin PCIe connector is present, which implies that the board can draw up to a theoretical 150W of power when loaded.





A ON Semiconductor NCP5395T 4-phase PWM is used that can be interfaced with i2C for voltage monitoring and control.







The DirectCU II cooler is a scaled down version of the ones used on higher end ASUS cards, with only 3 copper heatpipes on the heatsink base connected to a simple array of cooling fins.





The two fans used in the setup are actually different - a 10-bladed 72mm 0.35A model taking care of dissipating the heat from the GPU and the other 9-bladed 80mm 0.5A unit handling the toasty MOSFET cluster.







Overall soldering quality is very good and the board uses solid capacitors for longevity.

[siopao1984]

Software

ASUS has bundled their latest incarnation of the GPU Tweak overclocking control software (successor of SmartDoctor), currently at version 2.0.5.3. Unlike MSI's Afterburner the tool can only adjust voltages if you are using a card with ASUS's vendor ID set in the video card bios.





One interesting feature was the ability to scale the GPU clocks with the appropiate voltage level, making it a no-brainer for illterate users.





The tool can also contact a central server for updates to itself and the VGA bios.





On AMD's own Overdrive and most GPU overclocking tools, the core and memory frequencies are usually limited to an (unadventurous) range in the vBIOS. To work around this ASUS has included a "overclocking range enhancement" setting to override the predefined values. In addition to that, the 2D idle clocks can be disabled which forces the card to run at full speeds all the time to warm the earth and kill polar bears.







Overclocking





By setting the voltage to 1.3V (up from 1.21v), we could push the GPU clock speed to 1175MHz, which is a commendable 200MHz more than the already overclocked defaults and an impressive 315MHz over the reference design. As for the memory frequencies, we managed 1525MHz which is 22% higher than stock clocks.



Thermals / Cooling Dexterity

Methodology: We looped Unigine Heaven 2.5 on aggressive settings for 10 minutes on each run, and took the maximum recorded temperature from the on-die sensor. Ambient room temperature was about 20 degrees celcius.



Stock Voltage (100% Fan) Load Temperature: 47 degrees celcius (WOW)





1.3v Overclocked (100% Fan) Load Temperature: 55 degrees celcius (EXCELLENT!)

[siopao1984]

Test Setup



CPU: Intel Core i7-3960X @ 4817MHz 1.52v
Motherboard: ASUS Rampage IV Extreme (Bios 1005)
Memory: G.Skills RipJawsZ 2133Mhz DDR3 16GB Kit
Power Supply: Antec True Quattro Pro 1200W
Storage: Intel 520 series 250GB SSD
Graphics Cards / Drivers:
8.960 beta drivers:
ASUS HD7850 DirectCU II TOP
AMD Reference Radeon HD 7870
AMD Reference Radeon HD 7850
AMD Reference Radeon HD 7970 3GB
Sapphire Radeon HD 7950 OC Edition
ASUS Radeon HD 6970 DirectCU II 2GB
AMD Reference Radeon HD 6990 4GB

295.73 drivers:
MSI N580GTX Lightning Xtreme Edition 3GB (Nvidia 290.36)



Benchmarks:

3DMark11 Performance Preset - At 720p resolutions where things are more cpu bound, the ASUS excellent overclocks helped the HD7850 to catch up with its more illustrous brothers, even beating the significantly more expensive HD 7950 (which was at stock of course).





3DMark11 Xtreme Preset - No fairy tales here at 1080p, but the high frequencies does help the comparatively cheap HD 7850 to make a better impression of itself.





Unigine Heaven 2.5 and Game Tests - When tested at 2560x1600 (to eliminate any CPU bottleneck), the superior fillrate and memory bandwidth of the HD7970/7950 helps them to pull away from the rest. Again with the overclock, the ASUS card beats the stock HD7870 and even threatens the GTX580, which today costs almost US$100 and US$200 more respectively.









In our GPGPU test, it becomes a test of raw compute muscle. The GTX 580 performs badly because double precision floating point, some parties speculate, is deliberately castrated to protect Quadro/Tesla sales.





The ASUS HD7850 does consume abit more power than the reference card, probably due to a less efficient VRM design and its stock overclock.

[siopao1984]

Conclusion



The actual retail price is not known yet (AMD's reference card will be USD$249) but we feel that the ASUS HD7850 DirectCU II TOP represents excellent value for money, sometimes upstaging cards costing $100-$200 more at our overclocked speeds (Ed: but don't forget those cards can be overclocked too).

Pros
Surprisingly good performance at stock speeds
Relatively inexpensive
Good overclocking potential
Only require one 6-pin PCIe power connector (good for HTPCs or low power setups)
Up to 6-monitor Eyefinity, SteadyVideo UVD, PCIe 3.0, gradually maturing drivers


Cons
Higher power consumption than reference
Noisy at full fan speeds (no problems at AUTO)
Cooler could have been smaller to keep the card at 8-inches instead of 10.5 inch, since there was clearly a lot of thermal headroom

[denzel]

another hungry VC on the loose!!!!!! gaming for the win!!!!! hahaha so invest your money for that.

[sioti49]

yikes!!! buslot bulsa napud

[Rainerius]

Is it really worth it to spend extra with Direct CU models from Asus? Kato naa mga ing-ani style na card ok ba ang performance Or tungod lang sa good cooling it will give you more headroom for OCing?

[harhar]

Kung gusto kag beyond stock so kini paliton...