Here is a chart that specifies the disk drives that the systems originally came with, please use this as a reference: Model Catalog-Number CPU MHz RAM Floppy-Drives Hard-Disk DOS-Version DOS-in-ROM PSU-Watts 1000 25-1000 8088 4.77 128KB 5¼" 360KB - 2.11 - 54 1000A 25-1000A 8088 4.77 128KB 5¼" 360KB - 2.11 - 54 1000HD 25-1001 8088 4.77 128KB 5¼" 360KB 10MB 2.11 - 54 1000EX 25-1050 8088 7.16 256KB 5¼" 360KB - 2.11 - 28 1000HX 25-1053 8088 7.16 256KB 3.5" 720KB - 2.11 Yes 28 1000RL 25-1450 8086 9.44 512KB 3.5" 1.44MB - 3.30 Yes 25 1000RL-HD 25-1451 8086 9.44 512KB 3.5" 1.44MB 20MB 3.30 Yes 25 1000RLX 25-1452 80286 10 512KB 3.5" 1.44MB - 3.30 Yes 25 1000RLX 25-1452B 80286 10 512KB 3.5" 1.44MB - 5.00 Yes 25 1000RLX-HD 25-1453 80286 10 1MB 3.5" 1.44MB 40MB 3.30 Yes 25 1000RLX-HD 25-1453B 80286 10 1MB 3.5" 1.44MB 40MB 5.00 Yes 25 1000RSX 25-1455 80386sx 25 1MB 3.5" 1.44MB - 5.00 Yes 25 1000RSX-HD 25-1454 80386sx 25 1MB 3.5" 1.44MB 52MB 5.00 Yes 25 1000SL 25-1401 8086 8 384KB 5¼" 360KB - 3.30 Yes 67 1000SL/2 25-1402 8086 8 512KB 3.5" 720KB - 3.30 Yes 67 1000SX 25-1051 8088 7.16 384KB 2x5¼" 360KB - 3.20 - 67 1000SX 25-1052 8088 7.16 384KB 1x5¼" 360KB - 3.20 - 67 1000SX 25-1054 8088 7.16 384KB 2x5¼" 360KB - 3.20 - 67 1000TL 25-1601 80286 8 640KB 3.5" 720KB - 3.30 Yes 67 1000TL/2 25-1602 80286 8 640KB 3.5" 720KB - 3.30 Yes 67 1000TL/3 25-1603 80286 10 640KB 3.5" 720KB - 3.30 Yes 67 1000TX 25-1600 80286 8 640KB 3.5" 720KB - 3.20 - 67