Which Variants of Mauler One handed or 2 handed or any variant of the mauler
The textures are 1024x1024 dxt5 1.3mb each. You could try resizing them in ps, gimp, or paint.net to 512x512 and save in dxt1 format. That should help them alot.
Seems 1H & 2H maulers equally give a performance hit (the ones with all the extra spikes; under Oblivion\ Meshes\ Weapons\ Templar\ Club). Specifically when an enemy or enemies is/ are equipped with a mauler and in my view. I used the player.additem command to get a couple, then killed some bandits. After they're dead, I removed all other weapons from their corpse and put a mauler in their inventory. Then when I move my view back and forth across the corpse, I notice a performance decrease on framerate/ more "choppiness." Strange thing is, if I simply remove the maulers from my inventory and put them on the ground, my PC's performance is find. Even with the bandit's corpse in view with the maulers, but when I put them in the bandits inventory (with no other weapons), then I get the performance hit.
If it matters I'm running Oblivion on 1080p with dual (Crossfire/ SLI) Sapphire Radeon 3870 Toxic edition graphics cards.
Unfortunately all I have for an advanced texture editing tool is Photoshop 5.0. I imagine that's rather dated.

Update: After using the PyFFi script to optimize the NIF meshes, my performance has improved considerably with regard to the mauler weapons of OOO.