Review: Pentium 4 at 1,4, 1,5 and 1,6 GHz
Cache and Memory performance
Theoretically the Pentium 4 features peak transfer rates at 2,98 GByte/s for memory and FSB performance. While even the Pentium III is able to work with two channels of PC-800-RDRAM via the 820 chipset, its FSB at a maximum of 133 MHz limits its performance to a maximum of 0,993 GByte/s (1017 MByte/s).
In practical benchmarking the numbers are much smaller, for even the longest series of burst transfers does not last forever and DRAM of either kind needs its refresh cycles. Even a Pentium III at 1000 MHz with RDRAM is only able to get to 387 MByte/s when writing to memory. In comparsion, even the "slowest" Pentium 4 available at 1,5 GHz scores 737 MByte/s, and when reading from memory it is at 1175 MByte/s. As the following table shows, even an Athlon at 1200 MHz with FSB266 and DDR-SDRAM can not compete it here.
Athlon 1100-200 | Athlon 1200-200 | Athlon 1200-266 | Pentium III 1000 | Pentium III 1000 | Pentium 4 1400 | Pentium 4 1500 | Pentium 4 1600 | |
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Pentium 4 has the fastest memory interface of all PC microprocessors. These scores were taken with our benchmark tecMEM for DOS and rechecked with tecMEM32 for Windows2000/NT. | ||||||||
RAM- | PC133 | PC133 | PC266 | PC133 | PC800 | PC800 | PC800 | PC800 |
Move (Mbyte/s) | 222 | 231 | 291 | 199 | 186 | 737 | 741 | 738 |
Read (Mbyte/s) | 336 | 336 | 364 | 213 | 245 | 1175 | 1221 | 1283 |
Write (Mbyte/s) | 345 | 345 | 457 | 465 | 387 | 788 | 767 | 756 |
Aver-age R/W (Mbyte/s) | 341 | 341 | 411 | 339 | 316 | 982 | 994 | 1020 |
Even after a couple of runs the Pentium 4's performance while writing to memory still lowered with raising clockspeeds. The same effect could be noticed with other benchmarking software that measures memory performance. Until now we could not exactly evaluate if this is an incompatibility or a general problem with the Pentium 4. However, the effect is not present for transfers using Load or Move.
Our own benchmarks tecMEM and tecMEM32 are currently under development and not available for the public yet. Please bear with us.