Buffer size increase

Hey all,
I'm running Virus Ti2 with Serum, EWQLSO, and a number of other big programs. I used to be Reason exclusive and never had a problem with CPU. Now I'm working on an album in Cubase and my CPU is starting to get pretty high up after just 20 realtime synth tracks. I have the Virus TI2 as my audio card, set to 512 buffer size. I am wondering if another audio card like the Apollo Twin USB DUO would help mitigate overload by providing a higher buffer size, or if that wouldn't have any effect. I have only ever owned a couple of audio interfaces so I am not sure.

The reason I ask, is because I am using a home built PC with specifications as follows:
i7-5820K CPU @ 3.30GHz
16GB DDR4 2600
512GB SSD

Let me know what you all think. Obviously I can live with 20 realtime tracks and freezing them as I go, but the more the merrier.

Cheers

-Trenton

So I just got home and compared the TI2 interface track counts to my old Zoom H6 which supports up to 2048 buffer. I set up a session at 44.1/16 with multiple ridiculous Serum tracks each with 34 waves, 6 unison, reverb, delay, simple multiband compression, high-cpu multi band compression, tube compression, and a granular reverb on each. Oh, and 4 voice polyphony. The Virus crackled negligibly a couple times at 17 but could pull 18 with crackles, while the ZOOM was clean up until 17 and actually crackled, went silent, and malfunctioned at 18. I can pass this difference up to a simple trade-off in optimizations. The funny thing, is that experiment showed when my Cubase performance meter says it's at max, it is nowhere near max. So on my album that I'm working on, I can expect to have at least double the max on the meter.

My scientific method has shown that 512 on the TI2 equals that of a higher buffer size on another interface. This likely means higher quality buffer processing. I'd still like some feedback on high quality standalone interfaces like UAD, and if it's a worthwhile companion to enhance the Virus production experience.