D. J. Bernstein
Computer hardware

Advice for computer buyers

This page is obsolete. I have a new page explaining how to build the 2006.01.07 standard workstation.

The standard workstation

If you ask me what computer to buy, I'll start by suggesting the standard workstation. It's a very nice x86 (Intel-compatible) computer: solid, extremely fast, and reasonably inexpensive.

Of course, the computer market moves quickly, so the details of the standard workstation are constantly changing. I occasionally update this page with details of the most recent standard workstation.

If you build a machine along these lines, send email to djb-hardware a few weeks later reporting the hardware details and the results.

The 2005.08.23 standard workstation

Warning 1: The 2005.08.23 standard workstation requires a BIOS update. This is explained in my assembly instructions.

Warning 2: The 2005.08.23 standard workstation requires dri to be turned off in Linux; otherwise it freezes in dual-core AMD64 mode. This means removing the Load "dri" line in /etc/X11/xorg.conf. The same change is required in the corresponding file for FreeBSD, and presumably for other UNIX systems. It took me a while to track down this problem, and for a few weeks I assumed that there was a hardware problem (which is what a shared Linux/FreeBSD freeze normally indicates), but at this point it's clear that the hardware is fine and that the freezes were caused by dri bugs.

The 2005.08.23 standard workstation costs $911. (On 2005.11.16 it costs just $822: most importantly, the CPU has dropped to $322 and the hard drive has dropped to $106.) Notes on the price:

The standard workstation does not include a monitor, a keyboard, or a touchpad/trackball/mouse.

The following tables show the components of the standard workstation in detail. You can visit these warehouses online, select these components from the warehouse catalogs, and have the components shipped to you in a few days. Prices can change at any moment; use Price Grabber to find the latest and greatest prices.

The following components are available from ZipZoomFly:
$380AMD ADA3800BVBOX: 2000MHz L2-1MB Socket-939 Athlon 64 X2 CPU with a fan3 years from AMD92? (89 CPU; 3? fan) at +12V2
$95Asus A8V: Socket-939 UATA/SATA 305mmx245mm motherboard with audio and Ethernet; includes 2 SATA cables, UATA cable, ATA cable, floppy cable3 years from Asus20? at +3.3V, 20? at +5V, 10? at +12V1
$61Kingston KVR400X72C3A/512: 512MB DDR400 ECC memory in one DIMMlifetime from Kingston5 at +3.3V
$61Kingston KVR400X72C3A/512: 512MB DDR400 ECC memory in one DIMMlifetime from Kingston5 at +3.3V
$120Seagate ST3250823AS: 250GB SATA hard drive with NCQ5 years from Seagate34 at +12V1 (max for spinup), 5 at +5V
$36PowerColor RV6DL-B3: 64MB AGP 4X video card using ATI Radeon VE (7000) chip with VGA, TV, DVI outputs3 years from PowerColor10? at +3.3V
$52LG GSA-4163B: UATA DVD-ROM CD-ROM DVD+-R DVD+-RW DVD-RAM CD-R CD-RW drive (black)1 year from ZipZoomFly20? at +12V1, 8? at +5V
$19Antec TRICOOL 120 DBB: 120mm 1200RPM 39CFM 25dB fan, adjustable to higher speed3 years from Antec2? at +12V1
$0FedEx 2-day shipping

The following components are available from ebuyer:
$74Antec SLK3800B: 10.7kg case (black); one 1200RPM 38.94CFM 25dB case fan; 2.3kg SP400 power supply (max output watts: 390 at +5V, +3.3V, +12V1, +12V2 combined; 130 at +5V, +3.3V combined; 105 at +5V; 168 at +12V1; 180 at +12V2; 72 at +3.3V); two power-supply fans3 years from Antec10? for fans at +12V1
$13UPS 2-day shipping

Antec says that the SLK3800 is 18.3inx8.25inx18.6in (i.e., 464mmx209mmx472mm).

You may want to check local computer stores for cases and power supplies.

Variant: different low-end components

The DVD burner was selected entirely on the basis of price. If you don't want to write CDs or DVDs, downgrade to a $30 DVD reader.

The video card was selected almost entirely on the basis of price, but with the extra constraints of (1) DVI output, for sharper display on screens with DVI input, and (2) UNIX compatibility. The Radeon VE (ATI R100 chip) has been around for a while and is widely reported to work under UNIX without trouble.

If you're building a home computer, you may want to add a modem. Beware that most internal modems (and a few external modems) are "WinModems" requiring OS support. Linux and FreeBSD can both use the Lucent LT modem chipset.

The standard workstation no longer includes a floppy drive. You can add a floppy drive if you have any use for one.

Variant: more memory

You can put four DIMMs into the A8V.

I have a separate page discussing the importance of ECC memory.

Variant: single-core CPU

The Athlon 64 X2, like a dual-CPU computer, has two processing cores. Switching to a single-core computer means spending less money on the CPU. Of course, this also reduces the computer's speed for parallelizable operations.

Variant: larger drives

If you have more money to spend, the hard drive is one of the most obvious places to spend it. You can buy a larger drive; you can buy an external drive for backups; or you can buy several drives, and store data with parity using software RAID level 5. (Parity is an easy-to-use automatic backup mechanism: your latest data is still accessible even if a drive dies. Three disks with parity can store as much data as two disks without parity.)

Make sure you have enough cables for your drives. The A8V can support four UATA drives (two per cable) and two SATA drives (one per cable). The SLK3800B case has room for eleven drives.

I've switched from UATA to SATA, now that operating systems generally support SATA. Like UATA, SATA has ECC on data signals; unlike UATA, SATA has ECC on instruction signals, so a low-quality cable won't destroy data written to disk.

I generally opt for lower-RPM drives. Lower-RPM drives are less expensive; lower RPMs are less stressful, and therefore likely to last longer; and history suggests that lower-RPM models are much less likely to be badly manufactured than higher-RPM models. The performance difference (most importantly, the reduction in average seek time) is irrelevant: modern workstations have enough memory, so they rarely access their disks.

The Seagate ST3250823AS doesn't have quite the lowest price for its size, but less expensive drives have only a 3-year warranty.

Extra disks are a much better choice than tapes for backups. Disks used to be substantially more expensive than tapes, but they're now less expensive per gigabyte than almost all tapes. The only exceptions (Super DLT I tapes, about $0.40/gigabyte; LTO Ultrium tapes, about $0.30/gigabyte) require tape drives that cost over $1000. Even if you have so much data that you don't mind the cost of a tape drive, investing in tapes is silly: tapes wear out much more quickly than disks (a heavy-duty tape is rated for, at best, writing a few million gigabytes, which is equivalent to only about two years of disk use), and the replacement cost of disks is dropping much more quickly than the replacement cost of tapes. Of course, disks are also much faster than tapes.

Add-ons: video

The standard workstation doesn't include a monitor. You should buy a monitor if you don't already have one. On the other hand, if you have two or more computers in one room, you may instead want to buy a KVM (keyboard, video, mouse) switch so that all the computers can share one monitor. You may also want to buy a printer for high-resolution paper output, a scanner for high-resolution paper input, and a "webcam" for video input.

15" LCDs from various warehouses reached the magical price points of $299 in 2001 and $249 in 2003. For comparison, typical 17" CRT prices remained stable between $100 and $200. A typical 17" LCD with DVI input now costs slightly over $200. 17" LCDs are easier to read than 19" CRTs, are easier to move around, take less desk space, use less power, and will probably last a lot longer.

If you plan to do a lot of graphics work, you will want a larger monitor and perhaps a fancier video card.

Add-ons: audio

A typical motherboard includes an audio chipset with three connectors on the back of the computer: Loudspeakers, headphones, and earbuds connect to the line-out jack. Microphones and computer headsets connect to the microphone jack. Phone headsets have a different plug and won't connect to anything.

You will probably want a pair of earphones (headphones or earbuds) for private sound; you may also want a pair of loudspeakers for public sound. I find earbuds much more comfortable than headphones for extended use. Don't bother with earphones that use ceramic (ceramic strontium ferrite) or alnico (aluminum nickel cobalt) magnets; neodymium (neodymium iron boron) magnets provide several times more energy product (BHmax), typically 30 MGOe rather than 5 MGOe, without making a big difference in overall cost. A tiny $10 pair of earphones with neodymium magnets, such as the Sony MDR-E828LP earbuds that I'm using right now, can reach extremely painful volume levels without noticeable sound distortion.

(Actually, the standard workstation includes a small internal speaker on the motherboard. It's possible to use the internal speaker for 5-bit mono 22KHz sound. However, this requires support that most operating systems don't provide. In practice, the internal speaker is used only for occasional beeps.)

Alternative: prebuilt computers

Instead of selecting the components you want for your computer, you can buy a computer built by HP, Compaq, Dell, etc. through warehouses such as PC Connection or Outpost.

Prebuilt computers have several differences from the standard workstation described above:

If you do buy a prebuilt computer, I recommend buying one with a 3-year warranty.

Alternative: non-x86 processors

I sometimes buy overpriced processors so that I can see exactly how fast they are. This does not mean that you should buy them. When I publish software with optimizations for a Pentium-90, a PowerPC G4-533, and an UltraSPARC IIe-500, I am trying to help people take advantage of the hardware they already have; I am not suggesting that more of this hardware should be produced.

Apple's 2005.04.27 university price list (Collegiate Purchase Program Price List) shows a $1799 Power Mac G5 with two 2000MHz processors, 512MB non-ECC DDR400 memory, a 160GB hard drive, a video card, a DVD/CD-RW drive, a 10/100/1000 Ethernet card, a modem, a keyboard, and a mouse. (Apple's 2004.09.18 list showed a $1799 Power Mac G5 with two 1800MHz processors, 256MB non-ECC DDR400 memory, and an 80GB hard drive. Apple's 2003.07.19, 2003.12.13, and 2004.03.13 lists showed an $1199 Power Mac G4 with one 1250MHz processor and 256MB of slower memory.)

This Mac costs twice as much as the standard workstation and isn't anywhere near twice as fast. Hint to Apple: You'd sell a lot more of your software if you stopped trying to use it as a tool to sell your overpriced hardware.

I used to include UltraSPARC prices here as another example, but Sun seems to have given up on the UltraSPARC workstation market.