Not if it's normal paste. You can have good results with paste but you should spread it out yourself with a thin layer and remove all the black sealant used by Intel or you'll have small gaps under the IHS. If you use paste do not seal the CPU back up becasue it will dry out and you'll have to delid it again, we use LM becasue the thermal transfer is better but mainly becasue it never drys out under the IHS.
Keep in mind that the main reason behind delidding is replacing a TIM for something the most efficient and durable, paste will require changing after a "while". Reconsider using liquid metal.
I'd use LM too but I've seen results within a few C of LM with normal paste. As long as you know it won't last 5 years and you don't seal it up, there's really not a downside to just using paste.
It will still last a very long time.
I've done it both ways with the same results but to be safe you might as well paint it on. The best thing I've found for spreading is those cheap paint brushes with nylon bristles. They don't absorb any at all.
Now you do need to clear over the caps. On Haswell the die is very close to the row of caps and the LM spreads out over time.
LM at both the ihs and the die.
But don't overdo it.
Also insualte carefully the vrms and you'll be ok.
I got minus 15C at my cpu.
At 4.6Ghz I hit 100C at 2 mins of prime.Now it won't pass 85C after hours of stressing.