I'm having a problem with Oblivion running badly and I don't know if it's a system problem or due to mods, so I wasn't sure whether to ask in this forum or the hardware one, sorry if this is the wrong place.

I get bad stuttering and FPS drop especially in outdoor environments, it's not so bad indoors but outside it occasionally makes the game unplayable. Also semi-frequent CTDs. I tried lowering my texture size and reducing graphics settings like switching off AA. I also renamed my oblivion.ini so it would make a new file as I read somewhere on here that might help. But I have now started getting a Runtime error which CTDs when I try and move to a new area (specifically entering a city), which I wasn't getting before.

The game ran (almost) perfectly when it was out-the-box, with all graphics details set to maximum, and I do now have quite a lot of mods which is why I think they may be the problem, but I didn't expect them to make THAT much of an impact. I use Qarl's Texture Pack 3 'Redimized' which supposedly should work with 256mb video cards and mine is 512mb.

I use Streamline to cut down on draw distance and try to smooth out the game but my FPS still suffers.

My system settings are:
AMD Athlon 64 X2 Dual Processor 4200+
2GB RAM
Video card is an ATI Radeon HD4650 512MB
Windows XP Home

These are the mods I've got installed:

Masters for: Streamsave_3.ess00  Oblivion.esm01  EnhancedWeather.esm  [Version 1.3.5]02  Francesco's Leveled Creatures-Items Mod.esm03  Francesco's Optional New Items Add-On.esm04  Cobl Main.esm  [Version 1.72]05  Qarls_Harvest.esm06  Oscuro's_Oblivion_Overhaul.esm  [Version 1.34]07  Mart's Monster Mod.esm  [Version 3.7b3p3]08  FCOM_Convergence.esm  [Version 0.9.9MB3]09  Better Cities Resources.esm0A  Unofficial Oblivion Patch.esp  [Version 3.2.0]0B  UOP Vampire Aging & Face Fix.esp  [Version 1.0.0]0C  DLCShiveringIsles.esp0D  Unofficial Shivering Isles Patch.esp0E  SM Plugin Refurbish - SI.esp  [Version 1.05]0F  Better Cities .esp10  Francesco's Optional Chance of Stronger Bosses.esp11  Francesco's Optional Chance of Stronger Enemies.esp12  Francesco's Optional Chance of More Enemies.esp13  Francesco's Optional Leveled Quests-SI only.esp14  Francesco's Optional Leveled Guards.esp++  FCOM_Francescos.esp  [Version 0.9.9]++  FCOM_FrancescosItemsAddOn.esp  [Version 0.9.9]15  FCOM_FrancescosNamedBosses.esp  [Version 0.9.9]16  Natural_Habitat_by_Max_Tael.esp17  EnhancedWeather.esp  [Version 1.3.5]++  EnhancedWeather - Darker Nights, 50.esp  [Version Final]18  Enhanced Water v2.0 ND.esp19  LightsOut.esp1A  Cities Alive At Night.esp1B  AliveWaters.esp1C  AliveWaters - Koi Addon.esp1D  AliveWaters - Slaughterfish Addon.esp1E  Book Jackets Oblivion.esp1F  Days&Months.esp++  Item interchange - Extraction.esp  [Version 0.76]20  Q - More and Moldy Ingredients v1.1.esp21  Qarls_Harvest.esp22  RAEVWD Cities.esp  [Version 1.4]23  RAEVWD Imperial City.esp  [Version 1.4]24  SoT_Holiday.esp25  FF_Real_Thirst.esp26  Choices and Consequences.esp27  kuerteeIgnoringTheMainQuestHasConsequences.esp28  Rope Ladders v1.esp29  Cobl Glue.esp  [Version 1.72]2A  Cobl Si.esp  [Version 1.63]2B  FF_Real_Thirst, Cobl.esp2C  OOO 1.32-Cobl.esp  [Version 1.72]2D  Oscuro's_Oblivion_Overhaul.esp  [Version 1.34]2E  Choices and Consequences - OOO.esp  [Version 0.1]2F  FCOM_Convergence.esp  [Version 0.9.9Mb3]30  Choices and Consequences - MMM.esp  [Version 0.1]++  FCOM_EntropicOrderRebalance.esp  [Version 0.9.9beta2]31  FCOM_RealSwords.esp  [Version 0.9.9]++  FCOM_SpawnRatesReduced.esp  [Version 0.9.9Mb3]32  Mart's Monster Mod - More Wilderness Life No Gates.esp  [Version 3.7b3p3]++  Mart's Monster Mod - More Passive Wildlife.esp  [Version 3.7b3p3]++  FCOM_SaferRoads.esp  [Version 0.9.9]++  FCOM_LessRats.esp  [Version 0.9.9]++  Mart's Monster Mod - No Swarms.esp  [Version 3.7b3p3]++  FCOM_LessReaversInGates.esp  [Version 0.9.9]33  Mart's Monster Mod - Extra Wounding.esp  [Version 3.7b3p3]++  Mart's Monster Mod - Looting NPCs & Creatures.esp  [Version 3.7b3p3]++  Mart's Monster Mod - Less Reavers.esp  [Version 3.7b3p3]34  Mart's Monster Mod - Zombies for Body Meshes.esp  [Version 3.7b3p3]35  Mart's Monster Mod - Dungeons of MMM.esp  [Version 3.7b3p3]36  Mart's Monster Mod - Hunting & Crafting.esp  [Version 3.7b3p3]37  Mart's Monster Mod - Farm Animals.esp  [Version 3.7b3p3]38  Mart's Monster Mod - Diverse WaterLife.esp  [Version 3.7b3p3]++  Mart's Monster Mod - Slof Horses Complete.esp  [Version 3.7b3p3]++  Mart's Monster Mod - Diverse Runeskulls Loot.esp  [Version 3.7b3p3]++  Choices and Consequences - MMM - Looting NPCs & Creatures.esp  [Version 0.1]++  FCOM_DiverseGuardUnity.esp  [Version 0.9.9]++  Choices and Consequences - FCOM - Diverse Guards.esp  [Version 0.1]++  FCOM_HungersUnitySI.esp  [Version 0.9.9]++  FCOM_Archery.esp  [Version 0.9.9]++  FCOM_FriendlierFactions.esp  [Version 0.9.9]39  FCOM_MoreRandomSpawns.esp  [Version 0.9.9]3A  FCOM_MoreRandomItems.esp  [Version 0.9.9]++  Choices and Consequences - FCOM.esp  [Version 0.1]++  Mart's Monster Mod - Shivering Isles.esp  [Version 3.7b3p3]++  MMM-Cobl.esp  [Version 1.69]3B  Cyrodiil transportation network.esp3C  Region Revive - Lake Rumare.esp3D  Scribe Supplies.esp3E  za_bankmod.esp3F  Mart's Monster Mod - City Defences.esp  [Version 3.7b3p3]40  road+bridges.esp  [Version 4.5]41  Natural_Vegetation_by_Max_Tael.esp42  Harvest [Flora].esp  [Version 3.0.0]++  Harvest [Flora] - Shivering Isles.esp  [Version 3.0.0]43  Dungeon Actors Have Torches 1.6 DT.esp44  Kyoma's Journal Mod.esp  [Version 3.2.0]45  kuerteeInventoryIsABackpack.esp46  RealisticHealth.esp47  RealisticForceHigh.esp48  RealisticMagicForceHigh.esp49  RealSleepExtended.esp  [Version 2.3.4]4A  StealthOverhaul.esp4B  Stealth Entrances v1.esp4C  ZumbsLockpickingMod - OBSE.esp4D  ZumbsLockpickingMod - Hide Difficulty Addon.esp4E  No psychic guards harder fix.esp4F  Duke Patricks - Fresh Kills Now Alert The NPCs.esp50  RealisticLeveling.esp++  Level_Rates_Modified_x2.esp51  Let There Be Darkness - Cyrodiil + SI.esp++  Item interchange - Placement for FCOM.esp  [Version 0.76]++  Mart's Monster Mod - Resized Races.esp  [Version 3.7b3p3]52  Cobl Races.esp  [Version 1.52]53  Cobl Races TNR.esp  [Version 1.53]54  Cobl Races TNR SI.esp  [Version 1.53]55  Cobl Races - Balanced.esp  [Version 1.52]56  Better Cities Full.esp57  Better Imperial City.esp58  Better Imperial City FPS Patch.esp59  Better Cities - COBL.esp  [Version 2]5A  Better Cities Full FPS Patch.esp**  NRB4 Standard Road Record.esp++  Cobl Filter Late MERGE ONLY.esp  [Version 1.53]5B  Cobl Silent Equip Misc.esp  [Version 01]5C  Bashed Patch, 0.esp++  OOO-Magic_Script_Effect_Fix.esp  [Version 1.33]++  Duke Patricks - BASIC Script Effect Silencer.esp5D  Streamline 3.1.esp++  Gold Change II.esp++  Mart's Monster Mod - Friendlier Factions OOO.esp  [Version 3.7b3p3]5E  OWE&P -NW.esp5F  WindowLightingSystem.esp

I was wondering if anyone with better knowledge of these things can say if something is obvious as a big performance hog, or if there's anything I can try to make things a bit smoother.

Thanks for any advice.

FCOM and Better Cities are your biggest fps killers. Behind them, the RAEVWD city plugins are also hurting you.

This info is present all over the forum, so I'll just keep it brief:
Oblivion is cpu-intensive. NPCs and creatures/monsters eat up cpu time and cause fps to drop. Any mods which add lots of NPCs will hit you hard.
Oblivion Stutter Remover is a very helpful utility. It can't alleviate the strain on your cpu, but it does help with stutter and some types of crashes.

Other info: You shouldn't leave the BOSS unrecognized files at the bottom of your list. Almost nothing should load after the bashed patch. Certainly no merged mods should load there. Spend some time with the RAEVWD readme. There is info there about configuring the mod to be more fps-friendly. Consider choosing either FCOM or Better Cities, but not both.

gothemasticator

Try my site (see link in sig) to find more optimization options. However, as gothemasticator has already pointed out, the specs required for your mod list are beyond the power of your system. The "Redimized" version of QTP3 may work with 256mb graphics cards, but that does not mean that it works with 256mb graphics cards with tons of other stuff thrown in. For that version, a 512mb graphics card is preferable. You should try the "Redimized" reduced version of QTP3 if you really want to keep Qarl's. I would not run RAEVWD and QTP3 together with only a 512mb graphics card, but it seems as though it should work if you do not add any more graphics intensive mods (i.e., BC.) Make choices.

Graphics aside, your CPU is just on the weak side for running a bunch of AI intensive mods (i.e., FCOM, MMM.) Running FCOM, BC, Actors with torches and Region Revived mods together is too much. At least, get rid of the MMM add-ons and FCOM More XXX add-ons. Even Enhanced Weather could be hurting at this point.

Get rid of/cut down some or most of these:
City, AI, Clutter: Better Cities, Region Revived
Exterior graphics intensive: QTP3 Redimized, RAEVWD, Roads + Bridges, Enhanced Water, Cities Alive at Night
AI heavy: FCOM, MMM, OOO, Alive Waters, Duke Patrick's mods
Scripts: Actors with torches, Enhanced Weather, AWLS

Edit: Get rid of the Stealth Overhaul and Stealth Entrances mods too. Also, why are you loading those script effect mods? I do not see a conflicting magic mod. Get rid of Natural Vegetation. Use http://www.tesnexus.com/downloads/file.php?id=23783 instead. You probably should not use the high resolution version. AWLS and Lights Out seem sort of redundant, so choose one of them. In fact, choose one of each of the redundant mods (i.e., MMM Diverse Water Life or Alive Waters.)

Thanks for the advice guys. I'm working on a fresh install now and going to try and keep it lighter as I think I went overboard with the mods.

I've actually been reading your '50_Steps To CTD (Almost) Free FCOM+++ Game' thread Diviner and it's been really interesting and helpful, even if I don't understand a lot of it. I will definitely take a look at your site, maybe then I can understand PyFFI.

I'd really like to keep FCOM if I can. Better Cities would be great but I'll have to see if my comp can handle it. The only reason I used QTP3 was because BC wasn't working properly without it so I might get rid of it. And I will cull a lot of the other extra AI stuff.

Sorry for asking stuff that's been done to death. Every time I think I understand modding I find new things to mess up.

BC should work fine without QTP3. Just make sure you have the QTP3-specific options unchecked. Note that BC will cause an FPS in cities for almost any system. If you decide to keep some version of QTP3, get the PyFFI-optimized patch for it. (There is a link on my site...somewhere.) I think you could run FCOM+BC+QTP3 reduced, if you kick out all of Arthmoor's mods, so...

Remove these:
City, AI, Clutter: Region Revived
Exterior graphics intensive: QTP3 Redimized, RAEVWD, Roads + Bridges
AI heavy: FCOM and MMM spawn increasing add-ons, Alive Waters, Duke Patrick's mods
Scripts: Actors with torches
Choose the low power option for AWLS and Enhanced Vegetation (linked above) and get QTP3 Reduced and the PyFFI patch if you want to keep Qarl's mod.

You also remove:

4E  No psychic guards harder fix.esp

It only changes one GMST, which is also under settings and tweaks when you make your bash patch, so loading a whole esp is kind of a waste.