Logic Pro and Express share most functionality and the same interface. Logic Express is limited to two-channel stereo mixdown, while Logic Pro can handle multichannel surround sound; Logic Express also lacks support for TDM/DAE systems, high-end control surfaces and Distributed Audio Processing. Both can handle up to 255 audio tracks, depending on system performance (CPU, hard disk throughput and seek time). Logic Express 8 comes with 36 software instruments and 73 effect plug-ins, including almost all of those in the Logic Pro Package. Those that it doesn't include are Sculpture, a physical modelling synthesiser; the "vintage" instruments (the EVB3 tonewheel organ, the EVD6 Clavinet and the EVP88 Electric Piano), however a cut down version of these are included with the GarageBand instruments; Space designer, a convolution reverb effect; and delay designer, an advanced delay effect.