Ehi, guys, I have two problems:

1) Sometimes, during gameplay, Oblivion crashes to desktop. When to the desktop, a message like this (not ever) appears: The instruction 0x00762e7b has referred to the memory 0x00000110. The memory couldn't be read.

2) My game is slow when I ride my black horse. Strange: I have a Quad Core!!! I don't know if the mod called saddlebag can be the reason.

Here is my load order. Let me think what you think about it:

Active Mod Files:
00 Oblivion.esm
01 Oscuro's_Oblivion_Overhaul.esm [Version 1.33]
02 Unofficial Oblivion Patch.esp [Version 3.2.0]
03 Natural_Habitat_by_Max_Tael.esp
04 Natural_Vegetation_by_Max_Tael.esp
05 Natural_Water_by_Max_Tael.esp
06 Natural_Weather_by_Max_Tael.esp
07 Natural_Weather_HDR_by_Max_Tael.esp
08 DLCShiveringIsles.esp
09 Unofficial Shivering Isles Patch.esp [Version 1.4.0]
0A SM Plugin Refurbish - SI.esp [Version 1.30]
0B DLCHorseArmor.esp
0C DLCHorseArmor - Unofficial Patch.esp [Version 1.0.5]
0D SM Plugin Refurbish - HorseArmor.esp [Version 1.11]
0E DLCThievesDen.esp
0F DLCThievesDen - Unofficial Patch.esp [Version 1.0.5]
10 DLCThievesDen - Unofficial Patch - SSSB.esp [Version 1.0.4]
11 SM Plugin Refurbish - ThievesDen.esp [Version 1.30]
12 DLCSpellTomes.esp
13 DLCSpellTomes - Unofficial Patch.esp [Version 1.0.1]
14 DLCMehrunesRazor.esp
15 DLCMehrunesRazor - Unofficial Patch.esp [Version 1.0.4]
16 SM Plugin Refurbish - MehrunesRazor.esp [Version 1.30]
17 DLCFrostcrag.esp
18 DLCFrostcrag - Unofficial Patch.esp [Version 1.0.4]
19 SM Plugin Refurbish - FrostCrag.esp [Version 1.2]
1A DLCOrrery.esp
1B DLCOrrery - Unofficial Patch.esp [Version 1.0.3]
1C SM Plugin Refurbish - Orrery.esp [Version 1.11]
1D DLCVileLair.esp
1E DLCVileLair - Unofficial Patch.esp [Version 1.0.5]
1F SM Plugin Refurbish - VileLair.esp [Version 1.21]
20 Sonia.esp
21 Living Economy.esp
22 Oscuro's_Oblivion_Overhaul.esp [Version 1.33]
23 Living Economy - Items.esp
24 Cutthroat Merchants.esp
25 OOO-Water_Weeds.esp [Version 1.33]
26 Harvest [Flora].esp [Version 3.0.0]
27 Harvest [Flora] - Shivering Isles.esp [Version 3.0.0]
28 Harvest [Flora] - DLCVileLair.esp [Version 3.0.0]
29 Harvest [Flora] - DLCFrostcrag.esp [Version 3.0.0]
2A Knights.esp
2B Knights - Unofficial Patch.esp [Version 1.0.9]
2C SM Plugin Refurbish - Knights.esp [Version 1.06]
2D Bashed Patch, 0.esp

Thanks.

Oblivion is going to crash when running mods. That's a given. You'll just have to live with that. How often does your game crash? If it's 2 - 3 hours, that the norm. You aren't running a heavily modded game, but you could always try the LAA patch; that is if you are running a 64 bit OS and have 4GB or more of RAM.

What do you mean "the game is slow when you ride your horse"?

Thank you for your kind help.

The strange thing is that the game doesn't become faster when I reduce graphycal settings. When I am on my horse, Oblivion is not very fluid, to the point that running at the same speed while not riding, doesn't create the same problem.

I am Italian. So, sorry if sometimes I am not clear.

In other words: the game is fluid when I run, fight, jump without my horse; less fluid when I am on my horse (even if I only turn around myself).

Yesterday, I had three crashes in an hour. Today, zero crashes in 1,5 hours.

Do you think my load order is good?

Thanks again

Your load order looks okay. Did you run it through BOSS? If not, I would recommend that.

I will say: you are using Natural Environments. I don't recommend Natural Weather, or Natural Vegetation. I would suggest All Natural and Enhanced Vegetation. They are far better mods than NE.

I think you are talking about stuttering. If so, that is to be expected on a horse. Try downloading Oblivion Stutter Remover. That should iron out some of the stuttering problems you are having. I highly suggest it.

You could also try Streamline. That helps tremendously as well.

A quad core won't necessarily make Oblivion any faster. The game uses an outdated engine that is only really capable of using on of those cores. That's not to say that you can't get good performance on a quad core, but Oblivion cannot utilize it as well as a processor with less cores.

Thank you very much for this information. The strange thing is that my game stutters the same way even with low graphyc settings.

Malonn, thanks for the precious advices. I don't use BOSS, but I have Wrye Bash and OMM.
What file among these (http://www.tesnexus.com/downloads/file.php?id=23208) would you recommend?

Reducing the graphics settings will only improve FPS. It won't reduce stuttering. Stuttering is a result of cell information being loaded on the fly.

I recommend the Tripple WIP version. It contains all the latest code and default recommended settings. Read the thread though here on the forums. It has some great information in it.

Yes, there is a .dll file inside (called Oblivion).

I should put it in Oblivion\Data\obse\plugins (but my Oblivion hasn't \obse\plugins, so I have created these two folders on my own). Do you think this procedure is correct?

Yep. 100%.

You should definitely use BOSS. Without it, you will soon go crazy as your number of mods increases!!!

Thank you, guys.

I have pasted the .dll file correctly, but I haven't noticed any differences. And it is very very strange.

My PC is great, and it is not possible that I can't run Oblivion without stuttering. My Pentium 4 gave me better results than my quad core... it is very strange.
Yes, you could say that Oblivion doesn't support the benefits derived from a quad core technology, ok. But also in this case my actual PC should give me better performances.

I think there's something wrong with my video card or my processor. But I don't know how to prove this.

My PC:

Intel Core 2 Quad CPU Q8300 2.50Ghz
3,5 Gb RAM
XP Professional Service Pack 3
Video Card: ATI Radeon HD 5600 1,1 Gb