PostgreSQL as in-memory database 2

Hello again :(
There is a good and bad news. The good new is that the described scenario worked whit out any problem. I was able to mount and to create tablespace in memory.
Now I'm publishing the results so you can make your own conclusions:
N = Normal DB on HDD
V = Virtual in memory DB

INSERT 1 Row
N: 0.0095579624176
V: 0.00312209129333

INSERT 10000 Rows
N: 20.2224640846
V: 20.3045837879

SELECT 10000 Rows
N: 1.2087290287
V: 1.10954594612

SELECT 1 Row with LIMIT
N: 0.00473999977112
V: 0.00209808349609

SELECT 1 Row with WHERE
N: 0.00404500961304
V: 0.00110793113708

SELECT 10000 Rows using LIKE
N: 1.10466790199
V: 1.10219192505

SELECT 1 using LIKE
N: 0.163216114044
V: 0.143918991089

DELETE 1 Row
N: 0.0117321014404
V: 0.00280213356018

DELETE 100 Rows
N: 0.00914406776428
V: 0.00478386878967

DELETE 10000 Rows
N: 0.344476938248
V: 0.0865640640259

UPDATE 1 Row
N: 0.00603103637695
V: 0.00130820274353

UPDATE 10000 Rows
N: 0.158715963364
V: 0.48292517662