Actually-
Radeon VE- Is targetted at users who want dual monitors. I'm not sure whether the VE includes Hyper-Z or not, BUT the VE includes no T&L engine and only a single pixel pipeline (the Radeon has two). Overall the second pipeline is the bigger loss than the quasi-useless T&L engine (hardly any titles use T&L and I doubt many ever will). But without the two this card runs MUCH slower (read: not a great gaming card).
Radeon SDR- This card was supposed to go head to head with the Geforce 2 MX, but it ended up not seeing much action since the Radeon LE was released for practically the same price. The SDR memory slows it down a bit, but it is still on par and a little faster than the Geforce 2 MX, especially at higher resolutions and in 32 bit color.
Radeon LE- Radeon "Light Edition". I'm not sure if that is really what LE stands for, but that's what most people claim. Not officially manufactured by ATI, but instead by a partner company. There are no ATI logos on the card (just blank white spaces where they would be). Nonetheless, it is a Radeon card and uses the same drivers as all other cards. By default Hyper-Z is disabled on this card, but all you have to do to reenable it is download a registry tweaker (or just tweak the registry directly). It is also clocked lower at 143/143 MHz, BUT the memory is the same so you can clock it back up to 185 MHz or so with no problems. This card is available for around $80 and runs as fast as the GF2 GTS. The best buy for your money!
Radeon 32 OEM/Retail- A slightly more expensive Radeon version. Basically identical to the LE except you get ATI logos and Hyper-Z is officially enabled. The card is clocked at 166/166 MHz and overclocks to around 190 MHz. Beyond that the memory cannot handle it and you will start getting errors.
Radeon 64 OEM- This Radeon is identical to the Radeon 32 OEM and Radeon 32 Retail cards, but it has 64 MBs of memory.
Radeon 64 VIVO- The fastest Radeon available! Not only does this card have 64 MBs of memory, but that memory is also clocked to 183 MHz instead of 166 MHz. This higher speed memory allows you to overclock your card further, up to approximately 205 MHz. Beyond that your memory, once again, causes errors to start occuring. It also includes Video Input and Video Output, if you're into that kind of thing.
Overall there are only two cards really worth buying from the Radeon line. For the best value and bang for your buck there is the Radeon LE which is also your best overall buy. For the most overall power there is the Radeon 64 VIVO. The other cards are not worth buying because they are not significantly different from the Radeon LE and they are slower than the Radeon 64 VIVO.
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In comparison to the Geforce line of cards, the Radeon LE through VIVO are just as fast but have significantly better image quality.
In comparison to the Geforce 2 MX every single one of the Radeon cards, including the Radeon SDR is faster. It's really funny how people always go on about how the Geforce 2 MX is such a great card and a deal for the money. Truth is, the Geforce 2 MX is slower than just about every other value card on the market (including Radeon LE, Radeon SDR and Kyro 2) and costs more. If people actually took the time to look beyond Nvidia's hype at actual perofrmance they might realize this.
The Geforce 2 GTS cards are not significantly faster than the Radeon (if at all) and cost twice as much. You can buy a Radeon 64 VIVO for the cost of a Geforce2 32 MB card. Basically look to the Geforce line of cards if you want to waste a lot of money paying for Nvidia's marketing hype and 5 more fps in Q3 at 640*480*16 with all graphical settings turned off. ;-)