That's pretty much it. All those additional items translates into additional information that needs to be processed and retained in memory. My last game on a huge map went deep into the modern era, and by the time it ended, my savegames were over 1,600 megabytes in size.
Depending on your rig specs, your computer may or may not be able to handle the demands of big maps and/or the modern era.
Right on.
Worst is a Rise n Rule/ Total Realism addition using a larger then normal huge with high amounts of civs.
Here simplly adding an extra resource means more trading is possable at the same time, now add the new calculations from add-on improvements, its gets bad.. IT wouldn't if these new extras wern't being compounded by expanded tile counts (more citys then designers defination of "Huge") and extra civs.
Ya right now Its just to much for mass majority. Civ3 took many years for the majorty to be able to handle 'expanded in every way' type epics .
AFter ram toped at 512mb only new model Pentium 4s made a differnce from those who reported deley on the common but very poor L2 cache levels, of the Pentium 4 Northwood. (Dell supplied the world this model in vast amounts
)
The Prescott offered upgraded gameply atleast 10 steps up ladder as each model improved the game better then the last on 512ram rigs. Megahuge epic perfection was assured at the Cedarmill level before that, you had basicly the same only change came in greater archetucture and most important, a beefed up L2 supply
ITs a myth Ghz and ram + top G-card is all that will make the game fly. You can Do up a Pent4 with 3.4ghz, 2gigs memory, and best graphics card but If you run it on Northwood P4 engine your still going to watch your time die.
L2 cache is a big turntime buster, The ceder and late Prescott are so high in this supply it means pipe lenth was irrevelent. During even the most built up turn the rig never needed to seek out memory from Virtual cache (negating any AMD advantages) This is key in superb CIv interturn processing .
Civ4 is higher demanding so High clock speed is essential for late game when the CPU does need to call in more memory. With 3.2-4.0 ghz The relief pours in fast otherwise its a long journey down Intels long ass pipes. So Yes the clock speed does counts with Civ4. If you have dual I suggest you go back throught the monocore door and start overclocking. DOn't be thinking your utilizing more then one core. (turn off you backround programs before you start a game with Control+alt+del and you negate any dualcore advantage)
I havn't see any screenshots of globes filled up around midgame on one of these 3rd Xpak type mods to say CIv4 has reached a 'civ3 played on Cedermill' level of deley free superiority.
and that's why I 
Civ3.
