Bandwidth, latency, and HEXUS.PiFast
| Sciencemark 2 memory latency | |||||||
|---|---|---|---|---|---|---|---|
| AMD Phenom II X4 940 BE | AMD Phenom II X4 955 BE | Intel Core 2 Quad Q9550 | Intel Core i7 920 | Intel Core 2 Quad Q9650 | Intel Core 2 Quad Q9300 | Phenom II X4 810 | AMD Phenom II X4 920 |
| 55.52 | 55.44 | 46.24 | 38.11 | 46.17 | 46.2 | 56.73 | 54.53 |
The new AMD chip's memory latency comes in at expected levels, 20 per cent or so higher than the Intel Core 2 Quads and still further behind the Core i7 920.
| Sisoft Sandra 2009 SP2 (15.72) - float buffered | |||||||
|---|---|---|---|---|---|---|---|
| AMD Phenom II X4 940 BE | AMD Phenom II X4 955 BE | Intel Core 2 Quad Q9550 | Intel Core i7 920 | Intel Core 2 Quad Q9650 | Intel Core 2 Quad Q9300 | Phenom II X4 810 | AMD Phenom II X4 920 |
| 11.91 | 12.92 | 6.74 | 22.1 | 6.79 | 6.6 | 12.75 | 11.83 |
Memory-bandwidth results are around 10 per cent higher on AM3 - 955 BE and 810 - than on AM2+. Remember, we're running the DDR3 at 1,333MHz whilst the AM2+ numbers are derived from DDR2 at 1,066MHz.
AMD's AM3 memory-controller technology is such, being suited to both DDR2 and DDR3, that we foresee enthusiasts pushing 1.9V+ with quality modules. The same cannot be said about the sensitive Core i7 controller, but it provides oodles of bandwidth anyway.
| HEXUS.PiFast - calculation to 10m places | |||||||
|---|---|---|---|---|---|---|---|
| AMD Phenom II X4 940 BE | AMD Phenom II X4 955 BE | Intel Core 2 Quad Q9550 | Intel Core i7 920 | Intel Core 2 Quad Q9650 | Intel Core 2 Quad Q9300 | Phenom II X4 810 | AMD Phenom II X4 920 |
| 36.58 | 34.22 | 32.71 | 32.88 | 30.7 | 37.47 | 41.49 | 38.61 |
Bringing them together, the Phenom II X4 955 BE produces the fastest default-clocked HEXUS.PiFast time we've seen thus far from AMD chips. However, it's beaten, just, but the trio of Intel chips that cost between £10 and £60 more.
