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Pentium 4 Arrives

Toronto Star Fast Forward column for Nov. 23, 2000

Copyright ©, Myles White, 2000

See the end of this story for a series of surprises that have arisen since it was published.

This just in: As you may appreciate, the Computer Buyers' Guide supplement that arrived with today's Star took a while to put together and the lead time - the gap between when it was written and when it appears - was a little longer than it is for my weekly column. All this is by way of explaining why there's some slightly updated information here compared to the supplement. (Okay?)

Now that Intel is actually shipping its Pentium 4 processor, I've been able to give it a few tests. On one hand, they reveal pretty much what you'd expect; it's fast. But there are also a couple of surprises.

As predicted, the P4 resides on a 400 MHz front-side bus (the data pathway connecting it to main memory, processor chipset, BIOS (basic in/out system) and Accelerated Graphics Port (AGP) bus). That gives it the fastest base speed of any PC or equivalent system on the market. The processor itself has an internal speed of 1,498 MHz (nearly 1.5 GHz), which makes it the fastest PC processor on the market.

How fast? I used my favourite yardstick, the online version of Windows Magazine's WinTune ( www.winmag.com – then click on WinTune on the left-side menu). The unit I tested was a generic "White Box" provided by Intel. It came with 256 MB of Direct Rambus DRAM as its main system memory, and an nVidea Geforce 2 Ultra graphics adapter with 64 MB of memory. I also performed updated tests on a 500 MHz Pentium III and an 850 MHz AMD Athlon, both with 128 MB of SDRAM.

The Dhrystone test measures how well the processor handles integer math (whole numbers) and reports in millions of integer operations per second. The PIII/500 managed 1448, the Athlon/850 cranked out an impressive 2428, while the P4 produced 2591. (The Athlon 850 was only seven per cent slower than the 1.5 GHz Pentium 4).

The Whetstone test measures floating point operations, calculations of numbers with decimal points, in millions of floating point operations per second (MFLOPS). The PIII produced 580 compared to 837 for the P4. However, one of the surprises here came from the AMD Athlon/850: 993 on the same test - nearly 19 per cent faster than the P4.

MMX emulation tries to ascertain how well the processors will handle multimedia tasks. The P4 was the overwhelming favourite here with 256 compared to the PIII/500 (120) and the Athlon/850 (179). In earlier tests with a 1 GHz Pentium III, I discovered the Direct Rambus DRAM was about equal to the SDRAM in other systems and that's about what everyone else who tested found, too. That was then and this is now. Intel had been predicting that higher front-side bus speeds would make a big difference and it's apparent here. When measuring memory throughput in megabytes per second (MBPS), the P4's DRDRAM clobbered both systems (3286 MBPS for the P4, 1787 for the Athlon system and 833 for the PIII).

In short, the Pentium 4 is the current king of the hill, but not by as large a margin as the processor speed alone might make you think. The worrisome items for Intel that poked up like a red flag were its floating point operations and slim margin of performance advantage over the Athlon. And as other analysts across North America start reporting in, you can expect to hear more about it.

What else is new? Most of the differences between the Pentium III and Pentium 4 are highly technical. To keep it as simple as possible:

- All processors in the Pentium II, III, and 4 family engage in what is known as branch prediction. In essence the processor tries to predict what a program is going to want to do next. If it's right, the processor is able to execute the program more quickly. However, if it's wrong, it actually loses efficiency. Intel says it has tweaked the P4 not only to make predictions more quickly, but also to recover from wrong guesses more quickly, too.

- When a processor is running, it "ticks" over, millions of times per second. On each tick, something can happen to data that is moving around inside its components. However, when there is no data to work on because it's being held up somewhere, nothing happens and that wasted tick robs the system of efficiency. Intel has increased the speed of the P4's Arithmetic Logic Units to double its core speed.

- The 400 MHz system bus (aka front-side bus) moves data outside the processor much faster than systems based on other PC processors (66 MHz for Celeron, up to 133 MHz for Pentium III, 200 MHz for Athlon Thunderbird and Duron, or 266 MHz for Athlon Mustang).

- Intel has added yet another set of multimedia instructions the P4 can respond to. Called Streaming SIMD (Single Instruction Multiple Date) Extensions 2, you may see it referred to as either SIMD-2 or SSE2. In any event, the impact of the 144 new instructions won't be felt until there is software specially coded to take advantage of them.

How much? The system Intel sent out for evaluation, with a middling mix of other components (such as a DVD drive that wouldn't read CD-R discs) was valued at $3,400 US as it crossed the border (monitor not included), but this isn't a system anyone in the public will be able to buy - it was specially constructed for press evaluation. Because it will be the new top of the line, however, you can expect, when companies begin shipping P4-based PCs, that they'll be at the top of the price grid, in the $4,500-and-up range.

Surprise:

The Pentium 4 actually doesn't use a 400 MHz front-side bus. It uses a 100 MHz bus, but "Quad Pumps" the data so that four bits are sent along the bus where we might otherwise (i.e., in earlier processors) have only one. However it amounts to the same thing, so expect other reviewers to say it uses a 400 MHz bus without making the distinction.

Surprise 2:

After the review went to press, an Intel spokesperson got back to me and first crapped all over the Dhrystone and Whetstone tests, stating that, "Even the designer of the tests says they're no good for fast processors.

"Besides," added the P4 marketing manager, George Alps, "we didn't build those tests into the processor"(!)

"And furthermore," he added, "the P4 is optimized for Internet, gaming, and voice recognition apps, and not for business apps such as Word and Excel."

Also since my review went to press, Tom's Hardware has published its results against the Athlon (Mustang) at 1.2 GHz and determined that it's faster in many applications.

Surprise 3:

The Duron and Athlons don't run on 200 or 266 MHz busses, either. They use either a 100 or 133 MHz front side bus and "double pump" – sending two data bits instead of one (or four as Intel is now doing). See Surprise, above.

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