Is there any document available which compares Pervasive PSQLv11 and Microsoft MSSQL2005 or MSSQL 2008?

The links posted for older versions is no longer working.

Also what are the specifications for PSQLv11 for max database size, memory and numberof CPU's.

I found that Pervasive added support for multicore but does it support multiple processors??

I don't know of any papers. What kind of comparisons are you looking for?
As far as specifications, PSQL v11 has a maximum file size of up to 256 GB. Each file can represent one table in the database with a maximum of up to 65,355 tables in a database. As far as Memory, the 32 bit version of PSQL is limited to 2GB of memory. PSQL 64 bit is limited by the memory available. PSQL doesn't distinguish between cores and CPUs. I know of customers using the 64 bit version of PSQL with 128 GB of RAM and 16 cores/CPUs.

Thanks Mirtheil. This helps.

We are considering purchasing an app which uses Pervasive and are trying to understand server requirements and also see if we can move the data to our existing SQL Servers.

Usually the app vendor will give server requirements for their applications.
Moving the data may be more of an issue. PSQL and MSSQL store data very differently so the data isn't directly compatible. You might be able to use SSIS or the Pervasive Data Integrator tool to copy data from one database to another. If you want to run PSQL and MSSQL on the same server, it is possible but usually resource limitations (RAM, CPU, Disk, etc) cause performance issues. There is nothing specific that prevents both from running. I actually have PSQL, MSSQL, MySQL, and at one time PostgreSQL all installed on my test server. I never did significant performance testing on that server but never had any problems either.