Saturday, January 20, 2007

PC Evolution 2007

The original IBM PC released 27 years ago ran a 4.77 Mhz 8086/8088 CPU, 512 Kb of RAM memory on a 4.77 Mhz system bus with CGI 8-bit gray-scale video. It was meant to be a glorified adding machine, multiplying and adding columns of numbers and doing simple word processing. The XT model added an expansion slot and the AT two years later included the new 80286 processor at 10 Mhz.

PC's built in 2007 are expected to download and play video from a broadband connection, record and play HDTV simultaneously, or at least decrypt and output BlueRay or HD-DVD movies in surround sound to your plasma or LCD HDTV and home audio system. To do that, the video capabilities and system bus have to be jacked up like they are on steroids. Just compare one of these new monsters to your old PC.

The video card is a PC on a card. It may even have it's own fan and certainly has a huge heat sink. The CPU now dominates the board with a giant block of aluminum and fan atop it that makes your old CPU look puny. That's not because the silicon is bigger. It is now ΒΌ the size of your last CPU but contains two or more processors and 50 million transistors. All the rest is to support the 939 pin connectors and to dissipate the tremendous heat. Celeron CPU's run above the boiling point of water, 52 degrees Celsius (125F) but newer AMD processors run at room temperature if the huge heat sink and fan are working properly. The clock rate is being reduced, often 2 Ghz or less as the performance has continued to expand geometrically per Moore's Law.

Windows Vista Home Premium expects 1 Gigabyte of DDR memory, now 6400 times faster than SDRAM, a video card more powerful than your last PC with 256MB of dedicated video RAM and a CPU comparable to at least a 3 Ghz Pentium. To record and play high definition video in real time (without jerkiness) the main system bus has to run at 800-1000 Mhz with extra high bandwidth channels for video beyond what the AGP bus offered. The new PCIExpress16 standard handles 16 times more video data than it's immediate predecessor which blew away the old 8xAGP bus used a year or two ago. For gamers, this means you can see Shack sweat while playing the NBA video game. For the rest of us, it means our PC's will play or record high definition TV and movies from various sources. The PC is moving to a new role, more than just a communication device, it will coordinate our super high definition digital home multimedia experience.

I mentioned all that to explain what happened to me. I offered to upgrade a PC I had built for a friend a few years ago. I couldn't use the CPU, memory, or motherboard since all the standards had changed, but I thought I could use the old case, power supply, and CD-RW drive at least. I was wrong. The new board I purchased has a PCIExpress16 video slot that uses 75 Watts of power. So the board has an ATX12V 2.2 standard 24-pin power connector. If you check your old PC's power supply it has only a 20-pin connector. This standard hadn't changed since motherboards went from 5v to 3.3v almost a decade ago. So don't expect to upgrade that old PC without replacing the power supply. New ones also should include a special power tap for the newer SATA drive bus and maybe even a special vCore power connector for the new multi-core CPU's.