Here's mine.

All settings max out with AA (MSAA X2). FPS without fraps is as follows: 33min 40avg 55max.

Strategies:
ALWAYS be on the move to prevent the ALPHA CEPH from executing it's DRILL ATTACK which even the Nanosuit fails to withstand the damage, making it a one-hit-ko move if hit.

Weapon of Choice: X-PAC mortar (Explosive weapon)
Look for dead Ceph Devastator Units and utilize their X-PAC mortar which is far superior than the JAW.

THINGS TO NOTE:
MAX NANOSUIT: Look for glowing red catalystd/pods, these pods contains pre-charged energy that is enough to supply a huge amount of energy to your suit, which makes your suit activate the MAXIMUM NANOSUIT mode. When in this mode any ceph weapon you use will be supercharged with infinite ammunition. Also during the ALPHA CEPH battle, as long as the ALPHA CEPH is active, MAXIMUM NANOSUIT will NOT wear off after 15 seconds making you god-like.

If you're still having trouble you may want to use these:
Take advantage of the HACKABLE TURRETS around the map. Their extremely useful in taking down the ALPHAL CEPH's MINIONS & will also secure a small safe spot to recharge your Nanosuit's Energy when depleted.

Also note there are around 2-3 abandoned stationery CELL TANKS which are in the map for you to use whenever you like.

Piece of cake, just keep moving, use the biggest weapon you have, max out your suit and let bullets rain from everywhere.