Area = The Fountainhead; Upon first stepping through the tree door at the back of the palace into this area, the game slows to a crawl ... In fact crawl would be fast compared with this

There's a Gnarl Cultivator at the bottom of the tunnel which we see starts to move, but then the slow down occurs. Move the mouse, maybe 15 seconds later the screen will update slightly .... and repeat. Completely unplayable. Hold escape for approx 6 seconds and the game menu eventually comes up to exit.
The only mods we have affecting Shivering are USIP and UOP Supplementals, plus a few texture/mesh replacers, Vibrant, Bomrets Normals, RAEVWD SI, AWLS, Lush and Gaudy Landscape ... So most of my Install/Load order I believe are not a concern but will include just in case.
We have no lag anywhere else in the game, this one came as a bit of a shock to the system, so presume this may be an old known problem we probably missed in the early years of discovering TESIV problems similar to our recent discovery of the Bruma Statue problem and related fixes which needed an experienced eye to reference the fixes.
Does anyone have any recollection of such a problem?
Install Order:
Spoiler
Bain Packages:++ 000 - 1.Official GOTY SI KotN DLCs.7z (60B8D9AA) (Installed)++ 001 - 2.Official GOTY - BSAs.7z (7713F65A) (Installed)002 - ==--UOPs--==++ 003 - 3.UOP_v3_2_0_Manual_BAIN-5296.7z (BCBA7B56) (Installed)++ 004 - 4.UOMP_v1_5_Manual_BAIN-9969.7z (59895567) (Installed)++ 005 - 5.USIP_v1_4_0_Manual_install-10739.7z (79CE866D) (Installed)++ 006 - 6.Unofficial_Patch_Supplementals-27710-3-3-5.7z (576BF6E0) (Installed)007 - ==--Sounds--==++ 008 - 7.AS_Rain_and_Thunder_Sounds_V1.7z (DF3DBAB0) (Installed)++ 009 - 8.Ambiant_Sound_FX_1-2-29676.rar (93165CB5) (Installed)010 - ==--Land-LOD-Weather--==++ 011 - 1.Diverse Grasses 0.6 - Main.7z (082DA354) (Installed)++ 012 - 2.Vibrant Textures Weather DistantLOD 1.6 Bain-18677.7z (AF603CBE) (Installed)++ 013 - 3.Bomrets_Detailed_Normal_Maps_for_Vanilla_Version_1_1-18430.rar (19757949) (Installed)++ 014 - 4.RAEVWD-20053-1-9-1.7z (DE3AA518) (Installed)++ 015 - 5.RAEVWD_SI_Edition-20053-1-7.7z (437C0655) (Installed)++ 016 - 6.RAEVWD_Darker_Regal_IC_Texture_Pack-20053.7z (911475E6) (Installed)++ 017 - 7.RAEVWD_SI_Bomret_Textures-20053.7z (ABBE189F) (Installed)++ 018 - 8.Animated_Window_Lighting_System_v5-5-2-19628-1.7z (F35E4E9E) (Installed)++ 019 - 9.Phinix_Waterfix_v2-6680.zip (66703519) (Installed)++ 020 - 10.RedBag_-_Fog-33424.rar (694FDFF4) (Installed)++ 021 - 11.ImprovedSignsComplete-9498.rar (7B1F6919) (Installed)++ 022 - 12.Real_Wood_Road_Signs_Full-25429.rar (9FF09A61) (Installed)++ 023 - 13.Unique_Signs-25314.zip (FC0A6D23) (Installed)++ 024 - 14.Lush_and_Gaudy_Landscape_and_Grass_and_Tree_Mod_v1_2_BAIN-37336-1-2.7z (80D967EF) (Installed)++ 025 - 15.LowTriPolyGrass-33403.7z (C5ADC3C6) (Installed)++ 026 - 16.LowPolyTrees-33414.7z (9AA85BC1) (Installed)027 - ==--House-Dungeons-Castles-Quests--==++ 028 - Better_Dark_Brotherhood_Sanctuary-BAIN-22135-3-02.7z (75DEE90A) (Installed)++ 029 - Better_Abandoned_House_v1-22-BAIN-25319.7z (166C4B5C) (Installed)++ 030 - Better_Benirus_Manor_BAIN-4.7.1-18054.7z (DAFB5033) (Installed)++ 031 - Better_Benirus_Manor_-_Helping_Hands-23146-2-0.7z (D64883A4) (Installed)++ 032 - A_Brotherhood_Renewed-31773.7z (A848C6B3) (Installed)++ 033 - Aleswell_Cottage_ver_2-28702-1.7z (8C378AD3) (Installed)++ 034 - Vergayun-26643-1-0-7.7z (E3A80433) (Installed)++ 035 - Feldscar-30000-1-0-9.7z (E81DBDC5) (Installed)++ 036 - Faregyl_Village-21562-2-0-1.7z (B457CAD1) (Installed)++ 037 - Frostcrag_Village-37655-1-0-1.7z (DCAD282D) (Installed)++ 038 - TIE-35265-1-44.7z (9476501B) (Installed)++ 039 - Peruggias Passage v1.0.7z (B126FE5F) (Installed)++ 040 - Darkness Hollows1.6.7z (721CCD19) (Installed)++ 041 - PTArtifactsProperV11-29931.7z (911DD4EF) (Installed)++ 042 - ChapelShop.7z (51620888) (Installed)++ 043 - Weynon Retreat 1.5.7z (049F6FE9) (Installed)044 - ==--Body-Race--==++ 045 - 1.Cosmetic Compilation Revived - Capucine-17042.7z (00C83C68) (Installed)++ 046 - 2.All_Male_Bodies_Wizard_Installation_Package-37230-0-2.7z (6D8678BE) (Installed)++ 047 - 3.EVE_HGEC_BodyStock_and_Clothing_Wrye_Bash_BAIN_-24078.7z (85D9514C) (Installed)++ 048 - 4.IFT_Improved_Facial_Textures-v21-5643.7z (7E98DEC4) (Installed)++ 049 - 5.Optimized Facegen Files_1_2-35487-1-2.7z (299120F3) (Installed)-- 050 - 6.F-INevOblivion_1_0-BAIN-19021.7z (04553A96) (Not Installed)++ 051 - 7.Tabaxi_Version_2-9870.7z (6B71D144) (Installed)++ 052 - 8.Immersive_Tabaxi_Textures_Complete-22091-1-7.7z (1AFBAAEB) (Installed)++ 053 - 9.Foxs_Female_Argonian_textures_for_Exnems_body_v11-10506.rar (C068570D) (Installed)++ 054 - 10.IAFT_Improved_Argonian_Facial_Textures-6611.7z (2396DCF1) (Installed)++ 055 - 11.DesuChan_Kawa_BodyTextures-For-Khajiit_RM-HGEC-Ver_2_0_1-35579.7z (8F39DF88) (Installed)++ 056 - 12.Exlorians_Khajiit_Tail_for_HGEC-33745.rar (5E9DD6F1) (Installed)++ 057 - 13.The_n_Dywyll_Elves-35397.7z (AB7F2FE4) (Installed)++ 058 - 14.SP_Hair_Pack_Beta_Ver_1_0-30707.7z (4640AFFD) (Installed)059 - ==--Companion-Creatures--==++ 060 - Companion_Vilja_ver_3-28977.7z (7FACA9AA) (Installed)++ 061 - Xtudos_Noise_Rerduction_for_Vilja_ver_3_bsa-28977.rar (29BFEF29) (Installed)++ 062 - Companion_Vilja_3_0_1_patch-28977.7z (F7BBCB3B) (Installed)-- 063 - Vilja_Customization_pack_3_0_1-With-Alt-Xtudo-28977.7z (4D9E24FF) (Not Installed)++ 064 - 1em_Vilja_as_n_Dywyl_elf_by_Xtudo.7z (0D883500) (Installed)++ 065 - Eyen Vampire hunter-Luchaire-1_2-19822.7z (8CED423C) (Installed)++ 066 - Vilja_in_Aleswell_ver_1_1-28702.7z (12CD45D5) (Installed)++ 067 - Cool_Hair_for_Vilja-28977.7z (F89A9287) (Installed)++ 068 - TIE Cats Full v1.0-34872.7z (07AB2D2E) (Installed)++ 069 - slofs_horses_base_2-24312.7z (3EFC924F) (Installed)++ 070 - Espless_Slofs_Horse_Replacer-v1.2-27675.7z (2BCF76BE) (Installed)++ 071 - Zira_Clydesdale_Horses-v1.1-33560.7z (518CA4F2) (Installed)++ 072 - Xtudos_Zira_Clydesdale_Bruses-ver1.1-28977.7z (AFBE78A1) (Installed)++ 073 - Little_Baron_Vermin_1p5-35913-1p5.7z (A31D2C4A) (Installed)++ 074 - Little_Baron_Water_Beasts_v_1p3-36111-1p3.7z (B86F8943) (Installed)++ 075 - Little_Baron_Undead_Additions-37529-FINAL.7z (4527E919) (Installed)++ 076 - Deadlier_Creatures_V2-31882.rar (09BC037C) (Installed)077 - ==--Armour-Clothing-HGEC--==++ 078 - Sister_Of_Eisen-HGEC-25389.7z (A44B41F3) (Installed)++ 079 - Dark_Sisterhood_armor-28583.7z (6B13A5CC) (Installed)++ 080 - Underworld_armor-25734.rar (C5D41A92) (Installed)++ 081 - ExnemEC_Warrior01-13208.7z (AC25743C) (Installed)++ 082 - Gizmodian_-_Shell_of_the_Artifice-32969.7z (A6C9DF0E) (Installed)++ 083 - Captain_Molly_HGEC-28765.7z (BC382B0E) (Installed)++ 084 - Westwind_Rogue_HGEC-27319.7z (15755255) (Installed)++ 085 - IndigoArmor_v1_1_1_Fix-16645.7z (4F382ECC) (Installed)++ 086 - Elwing_Outfits_for_HGEC_v1_1-22330.7z (0C9700D0) (Installed)++ 087 - Gothic_Fetish_Outfit-36963-1-0.7z (305D3E7B) (Installed)++ 088 - CBDarkEnchantress-36199.7z (EC9F20A7) (Installed)++ 089 - SylvanArmor-37503-1-0.7z (F9B9D1C9) (Installed)++ 090 - BaronArmor_v2-35464-2-0.7z (C25C2A79) (Installed)++ 091 - Minibloomers_v1_1-BAIN-36177-1-1.7z (AFE898DF) (Installed)092 - ==--Weapons--==++ 093 - SothaDagger_-_The_Ornate_Dwemer_Blade-24236.rar (A9231713) (Installed)++ 094 - Nicos_Tabaxi_Bows_v1_0-17444.rar (41579318) (Installed)++ 095 - Blade of Woe and Sufferthorn Replacer.rar (92842CB0) (Installed)++ 096 - Kodachi_Swords_1_1-36995-1-1.7z (836E56F8) (Installed)++ 097 - Pekka_Shields_v12-14821.7z (7B4ACE88) (Installed)++ 098 - Explosives_v1_2-32267-1-2.7z (30D87C38) (Installed)099 - ==--Misc-Placers--==++ 100 - Improved Soulgems for TIE.7z (C70A668A) (Installed)++ 101 - Better_Potion_Bottles_Reduced_1dot2-14347.7z (93FC23BE) (Installed)++ 102 - better.looking.toolsv1.2.7z (13B10721) (Installed)103 - ====Game UI - Mechanics====++ 104 - DarkUId_DarN_16_Manual_Version-BAIN-11280.7z (04E2711F) (Installed)++ 105 - Display_Stats_2_0_1-31855-2-0-1.rar (3AA3907A) (Installed)++ 106 - Metallicow_Cursor_Mod_v1-35856-1.7z (883CCACD) (Installed)++ 107 - Cyrodiil_Terrain_Map_v25-2634.7z (10CA4276) (Installed)++ 108 - nvde_Spell-31168.rar (0D190B53) (Installed)++ 109 - Duke Patricks - Combat Archery Rev 5.1.1.7z (52802798) (Installed)++ 110 - Streamline_31_BAIN-22170.7z (7592F61A) (Installed)++ 111 - Wrye Bash INI Tweaks Xtras.7z (FBD5993E) (Installed)++ 112 - OSR_4-1-24_RC_ini_TH3-23208-1.7z (B2213352) (Installed)++ 113 - FastExit_2-22410.zip (33FF14FA) (Installed)++ 114 - OBSE_-Elys-_Universal_Silent_Voice_v93-16622.7z (4249925D) (Installed)115 - ==Last==-- 116 - RefScope_2_1_2-21862-2-1-2.zip (A57B7DD5) (Not Installed)-- 117 - Kill_The_Statues-21008.zip (B5B0E6E4) (Not Installed)-- 118 - Update_My_Statue-3428.zip (0188D1B3) (Not Installed)-- 119 - Vilja_ver_3_Documentation-28977.7z (F549731B) (Not Installed)
Load Order:
Spoiler
Active Mod Files:00 Oblivion.esm01 Unofficial Oblivion Patch.esp [Version 3.3.5]02 Oblivion Citadel Door Fix.esp03 DLCShiveringIsles.esp04 Unofficial Shivering Isles Patch.esp [Version 1.4.2]** Oblivion Vwalk UOS.esp** DLCShiveringIsles Vwalk UOS.esp** DLCShiveringIsles Vwalk DG_DS UOS.esp++ RedBag - Fog.esp++ phinix-waterfix.esp05 WindowLightingSystem.esp06 diversegrasses.esp07 ImprovedSigns.esp08 Display Stats.esp [Version 2.0.1]09 Streamline 3.1.esp0A DLCHorseArmor.esp0B DLCHorseArmor - Unofficial Patch.esp [Version 1.0.6]0C DLCOrrery.esp0D DLCOrrery - Unofficial Patch.esp [Version 1.0.4]** DLCOrrery Vwalk.esp0E DLCVileLair.esp0F DLCVileLair - Unofficial Patch.esp [Version 1.0.6]10 DLCMehrunesRazor.esp11 DLCMehrunesRazor - Unofficial Patch.esp [Version 1.0.5]** DLCMehrunesRazor Vwalk UOP.esp12 DLCSpellTomes.esp++ DLCSpellTomes - Unofficial Patch.esp [Version 1.0.1]** EVE_StockEquipmentReplacer.esp13 BaronArmor.esp++ Blade Of Woe Replacer.esp14 Captain_Molly_HGEC.esp15 CB Dark Enchantress.esp16 Chapel Shop.esp17 Elwing.esp18 Explosives.esp19 Gizmodian - Shell of the Artifice.esp1A GizmodianSothaDagger.esp1B Gothic Fetish Outfit.esp1C Hentai DarkSisterhoodArmor.esp1D Kodachi Swords.esp1E LKF_EY_Vampirehunter.esp1F minibloomers.esp20 Nicos Tabaxi Bows.esp21 Pekka_Shields_Light.esp22 PTArtifacts.esp23 Sister_of_Eisen_HGEC.esp24 SylvanArmor.esp25 Underworld Armor.esp26 Westwind_Rogue_HGEC.esp27 ExnemEC_Warrior01.esp28 IndigoArmor.esp29 DLCThievesDen.esp2A DLCThievesDen - Unofficial Patch.esp [Version 1.0.9]2B DLCThievesDen - Unofficial Patch - SSSB.esp [Version 1.0.4]** DLCThievesDen Vwalk UOP.esp2C TIE.esp [Version 1.44]** TIE Vwalk.esp++ TIE Cats.esp2D LBVermin.esp2E LBUndeadAdditions.esp2F LBWaterBeasts.esp30 AleswellHomeQuest.esp31 Better Dark Brotherhood Sanctuary.esp32 Better Benirus Manor - Helping Hands.esp33 Better Benirus Manor.esp [Version 4.71]34 BrotherhoodRenewed.esp [Version 1.0.11]35 DarknessHollows.esp** DarknessHollows Vwalk.esp36 Peruggia's Passage.esp37 WeynonRetreat.esp38 DLCBattlehornCastle.esp39 DLCBattlehornCastle - Unofficial Patch.esp [Version 1.0.5]3A DLCFrostcrag.esp3B DLCFrostcrag - Unofficial Patch.esp [Version 1.0.5]** DLCFrostcrag Vwalk.esp3C Knights.esp3D Knights - Unofficial Patch.esp [Version 1.1]** Knights Vwalk UOP.esp** EVE_KnightsoftheNine.esp3E Feldscar.esp [Version 1.0.9]** Feldscar Vwalk.esp3F Vergayun.esp [Version 1.0.7]** Vergayun Vwalk.esp40 Faregyl.esp [Version 2.0.1]** Faregyl Vwalk.esp41 Frostcrag Village.esp [Version 1.0.1]** Frostcrag Village Vwalk.esp42 Better Abandoned House.esp43 EVE_ShiveringIslesEasterEggs.esp44 ImprovedSoulgems.esp [Version 1.11]45 Oblivifall - Ambiant Dungeon SFX.esp [Version 1.2]46 nvde Spell.esp47 Duke Patricks - Combat Archery.esp [Version 5.1.1]48 CCR - Capucine.esp49 n_Dywyll_Elves.esp4A Tabaxi Race 2.0.esp [Version 2.0]4B 1em_Vilja.esp [Version 3.1]++ 1em_Vilja_as_n_Dywyl_elf_by_Xtudo.esp++ 1em_Vilja_coolhair60.esp++ 1em_Vilja_Bruse_as_Clydesdale_horse_by_Xtudo.esp4C ViljainAleswell.esp [Version 1.1]++ AMB.esp++ EVE_KhajiitFix.esp4D Bashed Patch, 0.esp
Using the recommended Bashed Patch SEWorld Tests option to suspend Cyrodiil quests/scripts - No Companion Vilja in tow with this particular game save.
OBSE 0020b6
Tried copying the saves (including obse save) across to the laptop to try on a different machine - Same problem
Tried dropping all equipment/armour/clothing before entering the area - Same problem
Tried with/without the new Bashed patch Import Actors Spells for UOP (which IIRC was related to a shivering isles creature (cant remember which, but just in-case it was Gnarl related which I know have an un-usual capability in this regard)) - Same problem either way.
Tried .. Wild stab in the dark .. Turning off OSR Allowslowmotion - Same problem