High end workstations need more powerful PSUs than desktop PCs. Workstations usually have high performance graphics cards and RAID HDD arrays, which need much more power.
Generic workstations may use PSUs based on the ATX format, but with a higher power rating, usually around 800w as opposed to a desktop PSU that may be only 300w.
Branded workstations from HP, Dell and IBM will need a dedicated PSU for that particular model, so check the specification of your workstation to ensure you order the correct part. Bargain Hardware are experts in workstation PSU specifications, and will help you specify the correct part, from our extensive stocks of re-used and refurbished workstation PSUs.