Alpha/Linux Wiki

The UP1500 is a motherboard built by Samsung and released in 2001.

• 800 MHz EV68AL with 2/4/8 MiB external L2 cache ¹⁾ (8.5 GiB/s ²⁾)
• AMD-761 Chipset, ALi M1535D+ south bridge
• 4x 184-pin DIMMs, supports 128 MiB to 4 GiB of ECC Registered PC2100 RAM (2.13 GiB/s ³⁾)
• 1x AGP 4x (See limitations below)
• 3x 33 MHz 32-bit PCI slots
• DECchip 21143 Ethernet
• ALi M5451 Sound

• The AGP slot accepts only 3.3V signalling cards, effectively limiting the selection of video cards to those supporting AGP 2x ⁴⁾
• Not all AGP cards that fit the slot actually work, see UP1500 Compatibility.
• The IDE controller does not support 48-bit LBA, so hard drive sizes are limited to 128 GiB (137GB)
• IO space needed for PCI counts against the amount of memory usable by the AMD-761 ⁵⁾
• According to Ivan Kokshaysky, the UP1000, UP1100, and UP1500's AGP is limited to PCI transfers:

There is quite fundamental conflict between the Alpha architecture and x86 AGP implementation - Alpha is entirely cache coherent by design, while x86 AGP is not (I mean native AGP DMA transactions, not a PCI over AGP). There are no such things as non-cacheable mappings or software support for cache flushing/invalidation on Alpha, so x86 AGP code won't work on Nautilus.