Sapphire Radeon HD 7950 3GB OC Edition Review: GCN For A Better Price

[siopao1984]

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Coming almost a month after the launch of the AMD Radeon 'Tahiti XT' HD 7970 and the 'Graphics Core Next' architecture, the Radeon 'Tahiti Pro' HD 7950 is essentially a stripped down version (87.5%, 1792 out of 2048 Stream Processors) of its more illustrious sibling . The extra lead time and lower TDP requirements has allowed the usual AIB manufacturers to work on non-reference PCB layouts and cooling designs, giving end users more innovation and choice. Today we look at one such offering from Sapphire...

Read more: Sapphire Radeon HD 7950 3GB OC Edition Review: GCN For A Better Price by VR-Zone.com

[siopao1984]

Sapphire opted for a glossy box design with the same voluptuous female mascot in military camouflage which first appeared on the Sapphire HD 7970 that we reviewed earlier this month



Back of box



Accessories - mini-DP/HDMI/DVI-D display convertors, a pair of Molex to 6-pin PCIe convertors, Crossfire bridge and the mandatory documentation/driver CD



Front of card - Sapphire has used the same dual-90mm fan design on this card as its HD 6970/6950 models instead of the noisy reference blower



Sadly no backplate behind to prevent warping or shorts



With the cooler attached, the card measures 12 inches long (11.5 inch PCB).



Like the HD 6950, it requires 2 x 6pin PCIe power connectors which is rated for 150W of additional juice on top of the power derived from the slot



Same layout and outputs as the HD 7970 - 2 x mini-DP, 1 HDMI and 1 DVI-D

[siopao1984]

After popping off the HSF, we find a heatplate covering some of the I/Cs and memory chips



Thermal pads on the metal heatplate



Sapphire HD 7950 fully exposed - we've seen a few designs of the HD 7950 PCB and this is probably closest to the reference version (with the obvious exception of the blue dye)



Same Hynix GDDR5 RAMs as on the HD 7970s - bodes well for overclocking (we've seen it go as high as 1700MHz with stock voltage)



Like the HD 7970s we've seen, this card uses the 8-phase CHiL CHL8228G Digital PWM. Also note the extra solder point on the left PCIe connector - which could imply multiple SKUs based on the same PCB



The dual bios switch and Crossfire connectors are also present on this board



A conventional heatpipe cooler (instead of the more expensive vapour chamber seen on reference HD 7970 cards) which should be good enough to handle the TDP of this card



Raised bump for core contact - water cooling affectionados will be delighted to know that the hole spacing is the same as the HD 7970 for their waterblocks



0.35A @ 12V 90mm Brushless DC Fans

[siopao1984]

The Sapphire HD 7950 is clocked at 900MHz on the core, 100MHz higher than the reference design (800MHz). Default VID of our card is 0.965V with a ASIC quality of 78.2%. Like the HD 7970, it also has PCIe 3.0 support which is currently only available on the SNB-E/X79 platform.



CCC Overdrive allows the clocks to be raised at high as 1100MHz and 1575MHz on the core and memory respectively. More on overclocking later...



Sapphire TriXX overclocking utility was not bundled with the board, but we had no problem downloading and getting it to work from their support website



Things are a lot more interesting on this tab than what CCC Overdrive offers - besides the extended clocks we could also set voltages up to 1300mV



Users can define custom fan profiles depending on acoustic needs or set a fixed fan speed



The ability to disable ULPS (without manually editing the registry) is certainly a nice feature to prevent idle bugs on Crossfire setups

[siopao1984]

Temperatures

For temperature testing, we set the fans to 100% manual speed and power control to +20% to mitigate the effects of any throttling



Dual Fan cooler result: 59 degrees (which is very good). We must also give praise that even at 100% the fans are still within reasonable noise levels especially if it is installed inside a sealed enclosure.



Overclocking

On stock voltage, we only managed a unimpressive 40MHz raise on the core (4.4%)



When voltages were raised to 1200mV, we could push the core clocks to a more respectable 1150MHz. Any more on the core voltage results in some kind of OCP/OVP kicking in causing the system to lock up. We left the memory clock at 1575MHz.

[siopao1984]

[siopao1984]

Benchmarks:

Right off the bat, the HD 7950 is just 6.5% slower than the HD 7970 despite having 12.5% less shaders. The difference narrows further once both cards are overclocked. Also, the previous generation cards are just spectators in this contest of the giants.



Same story here when the resolution gets raised to 1080p



In Unigine Heaven, we even see the overclocked HD 7950 beating the HD 7970, which shows that not all applications can benefit from the extra 12.5% of shaders



In notoriously GPU heavy Battlefield 3, the Sapphire HD 7950 comes precariously close to the reference HD 7970 as well, leaving the GTX580/HD 6970 in the dust and the HD 6990 a bloodied nose.



No surprises here either



Another DX11 title that cannot take advantage of the HD 7970's extra work units



As we can see in older games, both the Tahiti brothers are neck and neck



Its only in compute where we see the extra 12.5% Stream Processors count





Power Usage

Excellent showing from the HD 7950 here - it is the best of the lot here and consumes significantly less power both at stock and overclocked than the HD 7970

[siopao1984]

Conclusion



Price: US$479 / SGD$719 (The regular 800MHz reference design will cost US$449 / SGD$689)

[fishcracker]

me gustah!

[AlbertCruz]

P20,500
TipidPC.com | Sapphire HD 7950 3GB GDDR5