Virtual Primary Key = Slow

I've been discussing here a SQL 7 view which scrolls slowly when linked to
an Access 2000 MDB. After trying various things, I've distilled it down to
the following: when the linked view has a virtual primary key, it is slow;
when there is no virtual primary key, it scrolls quickly.

Looking at Profiler, I see that when there is no virtual primary key, Access
sends a simple select command to SQL Server. However, when there is a
virtual primary key, Access gets a list of primary key values, and then uses
those values to get records from SQL Server in groups of 10.

This may account for why the scrolling is slow when there is a virtual
primary key. However, I wonder if there's any way to improve performance or
otherwise work around this apparent bottleneck.

The MS literature says that creating a virtual primary key will not affect
performance. However, since different methodologies for obtaining data are
used with and without the virtual primary key, it seems that it does affect
performance, and certainly does in this situation.

Thanks,

Neil