The answer as far as most people are concerned is yes.  High Density non-ECC PC3200 is a non-standard configuration and to date no mainstream manufacturers make these modules.  Some high density PC3200 sticks are sold on auction sites as Samsung memory, however these modules are not made by Samsung.  They're unbranded and assembled using Samsung memory chips.  Just because my car has a Mercedes engine doesn't make it a Mercedes!  So the first issue is if using unbranded memory bothers you, steer clear.

More important however are compatibility issues.  Because High Density non-ECC PC3200 modules are non-standard not all motherboards work with them.  Some do, some might and some definitely don't.  Boards expecting memory to come in 64M bit high and 8 bit wide chunks don't always take kindly to memory served 128M bits high and 4 bits wide.  Some motherboards recognise high density 1 GB modules as only 512 Mb, in other cases motherboards refuse to POST.  One of the problems of determining compatibility is that unlike the best branded modules, where you're paying for consistency and testing, unbranded modules can exhibit inconsistency from module to module, so that one 1 GB stick of High Density non-ECC RAM might work fine on a SIS 755 based motherboard while a supposedly identical stick will cause a POST failure.

What works and what doesn't...

The following list comprises most of the motherboards stated to work with non-ECC High Density PC3200 memory.  Though bear in mind that whether your particular board works with High Density RAM, and if it does, whether it will work with all slots filled with High Density RAM will always be something of a punt:

INTEL 915; NVIDIA NFORCE3 250GB; NVIDIA NFORCE4 SLI; SIS 645; SIS 648; SIS 648FX; SIS 650; SIS 650GX; SIS 655; SIS 661FX; SIS 746FX; ULI CHIPSETS; VIA K8T800; VIA KM333; VIA KM400; VIA KT266; VIA KT333; VIA KT333A; VIA KT400; VIA KT400A; VIA KT600; VIA KT880; VIA P4X266A; VIA PM800; VIA PT800; VIA PT880.

The following additional boards might possibly work with some High Density modules - but equally they might not:

SIS 649; SIS 651; SIS 656; SIS 661; SIS 748; SIS 750; SIS 755; SIS 756; VIA APOLLO P4X400; VIA K8M800; VIA K8M890; VIA K8N800; VIA K8N890; VIA K8T890; VIA K8T900; VIA P4M800 PRO; VIA P4M890; VIA P4M900; VIA PN800; VIA PT800; VIA PT890.

As a rule of thumb it seems safest to assume that no Asus or Intel boards (with the exception of the 915) will work with High Density RAM.