For my own reference, I've tabulated the capabilities of Sun's UltraSPARC workstations. Sun named them all rather arbitrarily yet they have a mix of buses and interfaces, so having everything laid out in a table is of great help. Most of this information was taken from the Sun Systems Handbook; the notes are my own, based on my experiences.

Model Processor(s) Clock Cache Max RAM GA EOL Disk Periph.
Ultra 2 2 × UltraSPARC 167MHz
200MHz
512KB
1024KB
16 × 128MB
(2048MB)
6/96 5/00 SCSI SBus
UPA
2 × UltraSPARC II 300MHz
400MHz
2048KB
Ultra 5 1 × UltraSPARC IIi 270MHz
333MHz
360MHz
400MHz
256KB
2048KB
2048KB
2048KB
4 × 128MB
(512MB)
12/97 2/02 ATA PCI
Ultra 10 1 × UltraSPARC IIi 300MHz
333MHz
360MHz
440MHz
512KB
2048KB
2048KB
2048KB
4 × 256MB
(1024MB)
1/98 8/02 2×ATA-2(PIO4)
dual channel
4×32-bit 33MHz 5V PCI
UPA
Solid, small, and relatively quick. Large processor cache makes it faster than Blade 100/150. Takes only DIN-8 keyboards; no USB; on-board ATA-2 controller makes disk access very slow; mildly awkward upside-down maintenance configuration
Ultra 30 1 × UltraSPARC II 250MHz
300MHz
1024KB
2048KB
16 × 128MB
(2048MB)
5/97 2/99 1×Ultra2 SCSI 8-bit 40MB/sec
dual channel
PCI
UPA
Ultra 60 2 × UltraSPARC II 300MHz
360MHz
450MHz
2048KB
4096KB
4096KB
16 × 128MB
(2048MB)
6/98 7/02 1×Ultra2 SCSI 8-bit 40MB/sec
dual channel
3×64-bit 33MHz 5V PCI
1×64-bit 66MHz 3.3V PCI
2×UPA
Extremely solid machine; reasonably quiet; takes only DIN-8 (Type5) keyboards
Ultra 80 4 × UltraSPARC II 450MHz 4096KB 16 × 256MB
(4096MB)
11/99 7/02 1×Ultra2 SCSI 8-bit 40MB/sec
dual channel
PCI
UPA
Blade 100 1 × UltraSPARC IIe 500MHz 256KB 4 × 512MB
(2048MB)
2/01 11/02 2×ATA-66
dual channel
3×32-bit 33MHz 5/3.3V PCI
4×USB 1.x
2×1394
Very slow, economy machine; quiet (passive CPU heat sink); has undocumented jumpers to let it accept registered ECC memory, which is far more plentiful than the unbuffered ECC that it normally takes
Blade 150 1 × UltraSPARC IIi 550MHz
650MHz
512KB 4 × 512MB
(2048MB)
8/02 6/06 2×ATA-66
dual channel
3×32-bit 33MHz 5/3.3V PCI
4×USB 1.x
2×1394
Pretty slow; relatively quiet despite active CPU cooling (no thermal paste though); can be jumpered to take 550MHz or 650MHz processors on the same board; ONLY takes unbuffered ECC which is hard to find
Blade 1000 2 × UltraSPARC III 600MHz
750MHz
900MHz
4096KB
8192KB
8192KB
8 × 1024MB
(8192MB)
8/00 9/02 1×Ultra/Wide SCSI 16-bit 40MB/sec (SE)
single channel
1×FC-AL 1GFC 200MB/sec
3×64-bit 33MHz 5V PCI
1×64-bit 66MHz 3.3V PCI
2×UPA
2 × UltraSPARC III Cu 900MHz 8192KB
Powerful workstation; very quiet; CPU units are fickle and very delicate, and fiddling with them invites problems; CPUs easily run at 80°C and 670W PSU pulls a lot of power
Blade 2000 2 × UltraSPARC III Cu 900MHz
1015MHz
1050MHz
1200MHz
8192KB 8 × 1024MB
(8192MB)
5/02 7/04 1×Ultra/Wide SCSI 16-bit 40MB/sec (SE)
single channel
1×FC-AL 1GFC 200MB/sec
3×64-bit 33MHz 5V PCI
1×64-bit 66MHz 3.3V PCI
2×UPA
4×USB 1.x 2×1394
See Blade 1000 notes
Blade 1500 Red 1 × UltraSPARC IIIi 1062MHz 1024KB 4 × 1024MB
(4096MB)
9/03 5/05 2×ATA-100
100MB/sec
dual channel
2×32-bit 33MHz 5V PCI
2×64-bit 33MHz 5V PCI
1×64-bit 66MHz 3.3V PCI
4×USB 1.1
3×USB 2.0
2×1394
Reasonably powerful unit; memory is very odd; requires PC-2100 Reg ECC CL2.0 (most DDR266 is CL2.5). Shipped with OpenBoot 4.9.x which allowed it to take CL2.5 and big (unsupported) DIMMs (e.g., 2GB sticks of CL2.5 worked for me), but upgrading past 4.14.x prevents booting when CL2.5 memory is installed. Standard ATX motherboard and case; as a result, poor airflow, big fans, and mildly noisy.

Pushes the lower limits of general desktop usability; flash runs very slowly and mp3s sampled at 320kbps cannot play without skipping.
Blade 2500 Red 2 × UltraSPARC IIIi 1280MHz 1024KB 8 × 1024MB
(8192MB)
12/03 5/05 1×UltraSCSI 16-bit
SE/LVD
dual channel
2×ATA-100
dual channel
PCI
USB
1394
Blade 1500 Silver 1 × UltraSPARC IIIi 1503MHz 1024KB 4 × 2048MB
(8192MB)
2/05 6/06 2×ATA-100
100MB/sec
dual channel
2×32-bit 33MHz 5V PCI
2×64-bit 33MHz 5V PCI
1×64-bit 66MHz 3.3V PCI
4×USB 1.1
3×USB 2.0
2×1394
See Blade 1500 Red Notes.

Appreciably faster than the Blade 1500 Red.
Blade 2500 Silver 2 × UltraSPARC IIIi 1600MHz 1024KB 8 × 2048MB
(16384MB)
2/05 6/06 1×UltraSCSI 16-bit
SE/LVD
dual channel
2×ATA-100
dual channel
3×64-bit 66MHz 3.3V PCI
3×64-bit 33MHz 5V PCI
4×USB 1.1
3×USB 2.0
2×1394
Very powerful machine which uses a standard EATX motherboard and case; quite loud as a result. Has rear fan, CPU fans, dedicated memory duct fan, and dedicated hard drive cage fan. Pulls a lot of power (over 280W) with dual processors but supports huge amounts of RAM and very fast UltraSPARC processors.

As may be expected, significantly faster than the 1500 Red for general desktop use. Plays mp3s with high bitrates perfectly, although anything above basic flash video can get jumpy.

The Blade 2500 Silver has an integrated LSI53C1030 Ultra320 chip while the Red had an LSI53C1010 Ultra160 controller. Not all of the documentation for the Blade 2500 was updated properly, so it is extremely ambiguous; e.g., the Sun Systems Handbook lists the 2500 as being equipped with "one Ultra160 SCSI multimode" adapter while the Sun Blade 2500 Service, Diagnostics, and Troubleshooting Manual (817-5117-11) lists the onboard controller as a "dual-channel UltraSCSI IV 320 controller" in some places (page C-4) but not others (C-41).
Ultra 25 1 × UltraSPARC IIIi 1340MHz 1024KB 4 × 2048MB
(8192MB)
6/06 7/08 SATA
SAS
PCIe
USB
Ultra 45 2 × UltraSPARC IIIi 1600MHz 1024KB 8 × 2048MB
(16384MB)
5/06 7/08 SATA
SAS
PCIe
USB