If just a client getting definitions is an issue, James007's solution won't work with mixed platforms and every time a client is off more than a day (like weekends).
Example:
- SEPM downloads both new 32 and 64bit definitions daily at 7PM
- at the time GUP is on and clients should be off, hence the GUP populates its cache with the content downloaded for itself, 32 or 64bit, not both
- the day after, the clients which need the same content of the GUP will found it in the GUP, the rest will ask for what they need during working hours.
- any client not connected for more than a day (such as for weekends) will ask for a delta that the GUP did not download the day before.
Of course, you may also plan to never switch clients off so they can update during the night but maybe it is better to invest on the network link(s) instead of on the electricity bill.