[CentOS] which kernel do people use?

Lists wrote:
> On 10/24/2013 03:48 PM, Karanbir Singh wrote:
>> On 10/23/2013 10:30 AM, Morgan Cox wrote:
>>> If you want SSD + MDRAID you need to use a 3.8+ kernel to have TRIM.
>>>
>>> The speed difference between the stock 2.6.32 -> 3.10 kernel with SSD +
>>> MDRAID is insane.
>> has someone quantified what this 'insane' amounts to ?
>
> Going from HDD to SSD's gave us better than a 95% reduction in query
> times for complex queries using PostgreSQL on otherwise identical
> hardware. I wouldn't have believed it had I not seen it directly, for
> myself.

interesting datapoint for HDD vs SSD, but what about kernel versions? 
When using SSDs, did you need to use 3.8+ kernels as suggested in the 
quoted post, or do you use stock?
thanks