PC Technologies That Will Affect Your Mac

Thereis certainly a few of us out there, myself included, who believe that many technical innovations and technologies in the PC industry come from Apple ideas and products. What you might not realize, however, is that many PC industry innovations also make it into the Mac. This means that what goes on in the PC industry can be very important to the future of the Mac. Today, Iim going to look at PC hardware trends and technologies seen on display at the recent Intel Developer Forum that are going to have an impact on the Mac.


The main trend in PC processors that will affect the Mac is the growing emphasis on floating point operation speed. Intel largely designed the Pentium 4 around boosting floating point speed at the cost of integer performance. Intel did this because they see future PC usage centering floating point intensive tasks, like digital video, 3D graphics and voice recognition.

While Pentium 4 technology probably wonit be making its way into the Mac anytime soon, Intelis hardware will largely guide the development of future Mac software indirectly. Since most software development targets the PC, Power PC processors (or whatever will appear in future Macs) will have to at least come close to matching the floating point performance and functionality of future PC processors. Otherwise, we might be faced with Macs that cannot run the newest killer apps.

Right now, Mac floating point performance appears to be more than acceptable. AltiVec (Velocity Engine) really can make a large difference, as Steve Jobs illustrated with iDVD. However, with the Pentium 4 quickly ramping up to 2GHz and beyond and a new host of applications being written to use the Pentium 4is ample floating point power and SSE2, I donit think a 733MHz G4 is going to cut it for long. Mac hardware needs to keep up with PC processors in floating point performance or else future applications will outgrow Mac hardware.


With their newest generation of Macs, Apple went with 133MHz SDR SDRAM. If Apple plans on keeping performance up with the rest of the industry, they will have to move to faster memory with their next generation systems. This is especially important for floating point operations, where memory bandwidth is often a bottleneck. Since Apple isnit large enough to set their own standards, theyill have to choose from what is available in the PC market.

There are currently three forms of memory vying for use in future PC and Mac platforms, SDR SDRAM, DDR SDRAM, and RDRAM. With that in mind, Iim going to give a quick rundown of the three competing types of memory so you know what memory choices Apple is choosing from:

SDR (Single Data Rate) SDRAM is used in most PCs and all Macs today. SDRAM is the old standard though, with the slowest overall performance, and will be phased out of production over the next several years. Current high-end SDR SDRAM systems run at 133MHz on a 64-bit bus, giving them about 1GBps of peak theoretical memory bandwidth. ATI is currently working on a PC chipset with integrated video that will use 133MHz or faster SDRAM on a 128-bit bus, doubling the bandwidth.

DDR (Double Data Rate) SDRAM is used in systems based around the newest high performance VIA, ALi, and AMD chipset. DDR is an evolutionary next step in SDRAM, doubling data bandwidth over SDR, and has widespread industry support. Current high-end DDR SDRAM systems run at 100 or 133MHz on a 64-bit bus, sending data on the rising and falling edge of each clock, giving them about 1.6-2.1GBps of peak theoretical memory bandwidth. DDR SDRAM also uses less power than SDR SDRAM, which makes it well suited to performance notebooks.

RDRAM is used in systems based around Intelis i820, i850, and i860 chipsets, as well as the Sony PlayStation2. Current RDRAM systems run at 400MHz on a 16-bit bus, sending data on the rising and falling edge of each clock, giving them about 1.6GBps of peak theoretical memory bandwidth. Due to the narrow 16-bit bus, more than one RDRAM channel is often practical, giving plenty of bandwidth headroom. For instance, the i850 chipset for the Pentium 4 uses two channels, giving it 3.2GBps of bandwidth.

I expect Apple will go with DDR SDRAM in next-generation machines. RDRAM prices and supplies are not as stable as SDRAM, making DDR SDRAM the safest choice, though probably not the fastest.


Intel is pushing I/O (input/output) forward on several fronts. Slow I/O can still bottleneck a fast processor with fast memory. USB 2.0, Serial ATA, AGP 8x and PCI-X are all technologies Intel is pushing to bring I/O speed and usability up to snuff, and Apple will likely adopt all of these forms of I/O:

USB 2.0

USB 2.0 is planned to run at 480Mbps (Megabits per second). Intel expects it to be the standard for hooking up external consumer peripherals, including hard drives, scanners, and cameras. This will make USB 2.0 a close competitor to IEEE 1394, a.k.a. FireWire.

USB 2.0 is not technically superior to FireWire. For example, unlike FireWire, it doesnit have the ability to send data directly between two devices, instead having to through the computeris USB controller and then back out to the other device. But USB 2.0 will eventually be built into most PC chipsets, which will give it a large advantage. With FireWire built in, a Mac wonit necessarily need USB 2.0, but if Apple wants to insure the Macis place as the "digital hub," USB 2.0 will show up on the Mac.

Serial ATA

Serial ATA is Intelis slated 2-wire replacement for the current ATA/100 standard, which uses bulkier 80-wire parallel cabling. Like ATA/100, Serial ATA is intended for hooking up internal storage. It will start with 1500Mbps of bandwidth, dramatically more than ATA/100is 800Mbps. Serial ATA also has a clear upgrade path to 3000 and 6000Mbps. On the PC side, Serial ATA should start phasing in during 2002. Since it is the slated replacement for ATA/100, Apple will most likely transition to using Serial ATA around the same time as the PC industry.

AGP 8x

AGP 8x is the next industry standard graphics interface, which should double bandwidth over todayis AGP 4x. If Apple doesnit intend on losing more 3D graphics performance ground to the PC, they will adopt AGP 8x. One advantage of AGP 8x is that it can deliver quite a bit of memory bandwidth to video integrated into a chipset. In other words, AGP 8x could be part of a low-cost and quick (usually two ideas that donit mix) graphics solution for future iMacs and PowerBooks. This means that even Appleis low-end product could have professional level performance, a potential weapon in the consumer space.


PCI-X is the name of a new high-speed part of the PCI 3.0 spec, intended for adding in-the-box card upgrades. PCI-X will run at 133MHz on a 32-bit or 64-bit bus with improved bus protocols, giving it up to about 1GBps of real-world bandwidth. In comparison, most PCI busses today run at 33MHz on a 32-bit bus, with inefficiencies cutting real performance well below the interfaceis theoretical peak bandwidth of 132MBps. PCI-X cards and busses will be backwards compatible with earlier PCI cards, which makes PCI-X an easy path to greater bandwidth. Considering Appleis willingness to move to 66MHz and 64-bit PCI, I expect Apple will move to PCI-X along with the rest of the PC industry.

Innovation and Evolution

And there you have it, a look at future PC technologies and technological trends that will impact the Mac. Itis interesting that, while Apple is viewed as the innovator, tremendous amounts of PC technology are now appearing, and will continue to be appearing, on the Mac. If this offends your Apple sensibilities, realize that none of these PC technologies are groundbreaking. The words "evolutionary and conservative" are far more accurate. None of them push the bounds like a titanium notebook or a Unix for the masses. Instead, these PC technologies provide firm ground from which Apple can push forward.

Jon Simon was the Assistant Editor of Sharky Extreme, publishing technical and industry pieces about the PC while hiding his history as a Mac consultant. Nowadays, he is pursuing his dream of a permanent European vacation. Have PowerBook, will travel.