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.

Memory performance

	Athlon 1100-200	Athlon 1200-200	Athlon 1200-266	Pentium III 1000	Pentium III 1000	Pentium 4 1400	Pentium 4 1500	Pentium 4 1600
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.