AMD has been targeting mainstream computing for a while now.
Its combination of good performance for affordable price has seen it claw back into the graphics market with its most recent generation of cards, and now it looks positioned to do the same with the CPU side of the business. While it doesn't intend to challenge Intel's top performing Core i7 CPUs for now, AMD's latest, the Phenom X4 955 Black Edition (BE), launches a broadside across the bow of Intel's mainstream quad-core processors — in particular the Core 2 Q9550.
Black boxed bliss (Credit: AMD)
Based on AMD's AM3 socket, the 955 is a quad-core, 45nm process CPU running at 3.2GHz, as a result of a 16x multiplier on top of a 200MHz bus. It has 6MB shared L3 cache, along with 64+64KB data + instruction L1 and 512KB L2 cache per core. Being a flagship chip, it's quite a power sucker, at 125W TDP. Being a Black Edition chip, it's also multiplier unlocked — and this combined with the split plane voltage introduced on AM2+ should mean some fairly decent DIY speed increases.
Moving to 938-pin AM3 means a few things; firstly DDR3 support, and secondly the 128-bit integrated memory controller has had its Hypertransport link bumped from 1.8GHz on AM2+ to a healthy 2.0GHz. The processor should be backwards compatible with AM2+ boards, but be warned you'll only be able to use DDR2 on these, and your vendor will need to have released a BIOS update to support the CPU.
Test configuration
We've compared the Phenom II X4 955 BE against its price match competitor from the Intel camp — the Core 2 Q9550. Let's take a closer look at the CPUs on test.
| AMD Phenom II X4 955 | Intel Core 2 Q9550 | |
|---|---|---|
| Clock Speed | 3.2GHz | 2.833GHz |
| Multiplier | 16 | 8.5 |
| Multiplier unlocked | Yes | No |
| Bus speed | 200MHz | 333MHz |
| Memory controller link | 2000MHz | 1333MHz |
| L1 cache | 64+64KB data + instruction per core | 32+32KB data + instruction per core |
| L2 cache | 512KB per core | 6MB per dual-core |
| L3 cache | 6MB shared | N/A |
| Socket | AM3, AM2+ | LGA775 |
| Memory supported | DDR3/DDR2 | DDR3/DDR2 |
| Process | 45nm | 45nm |
| Supported instructions | MMX, SSE/2/3/4a | MMX, SSE/2/3/4.1 |
| Vendor specific instructions | AMD64, Extended 3DNow!, Cool'n'quiet, NX bit, AMD-V | Intel 64, iAMT2, EIST, XD bit, TXT, Intel VT |
| TDP | 125W | 95W |
Intel's been outperforming AMD for clock ever since the introduction of the Core architecture, while AMD has hit back on the price platform. AMD's jump to 45nm is finally seeing it claw back some market share, and it's not so much this generation as next generation where we're likely to see some interesting things happen. Let's take a look at the test benches that put the grill on both the Intel and AMD sides.
| Platform one | Platform two | |
|---|---|---|
| CPU | AMD Phenom II X4 955 BE | Intel Core 2 Q9550 |
| Heatsink | Thermalright Ultra Extreme 120 | Thermalright Ultra Extreme 120 |
| RAM | 2x Corsair 2048MB XMS3-1600, 11-11-11-30-41-1T | 2x 2048MB Corsair XMS2-1066, 5-5-5-15-22-2T |
| Motherboard | Asus M4A79T | MSI P7N Diamond |
| Graphics card | Asus 8600GT Silent (Driver 186.18) | Asus 8600GT Silent (Driver 186.18) |
| OS drive | Intel X25-E 32GB | Intel X25-E 32GB |
| Storage drive | Seagate Barracuda 7200.11 1.5TB | Seagate Barracuda 7200.11 1.5TB |
| Optical drive | Asus DRW-22B1ST | Asus DRW-22B1ST |
| Operating system | Windows Server 2008 SP2 64-bit | Windows Server 2008 SP2 64-bit |
Note that the Core 2 Q9550 is running with DDR2 compared to the Phenom II X4 955 BE's DDR3 — and although the P7N Diamond is certified for DDR2-1333, it will not run higher, and despite loosening the timings the RAM would not run faster than 1066MHz on this board. As such, we've opted to provide benchmark scores on the Phenom II platform for both the stock 1600MHz DDR3 and downclocked to 1066MHz.
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